Tuesday

February 21, 2017
Number of results: 25,876

**physics**

The figure below shows the speed of a person's body as he does a chin-up. Assume the motion is vertical and the mass of the person's body is 73.4 kg. Determine the force exerted by the chin-up bar on his body at the following times. t=0s, speed= 0cm per second; t= .5s, speed= ...

*October 10, 2010 by Amber*

**Two bus trvl in opposite direction frm that same rtarting point.if d speed of 1 is twice d speed of d other and de 240km**

Apart at the end of one hour,what is the speed of each bus?

*September 7, 2016 by PHYSICS*

**Physics**

A .324 kg air track glider moves linearly with an initial speed of 1.37 m/s.In order to increase the speed of the mass, 7.31 J of work are done. What is the final speed of the glider? (Ignore the negligible friction)

*January 26, 2017 by Anonymous*

**physics**

A 0.55 kg object connected to a light spring with a force constant of 20.0 N/m oscillates on a frictionless horizontal surface. If the spring is compressed 4.0 cm and released from rest. (a) Determine the maximum speed of the object. (b) Determine the speed of the object when ...

*June 29, 2011 by Sarah*

**Science..help plz...**

Can you define speed, motion, constant speed and average speed? And can you get me there formulas? Example-Distance over speed THANKS MUCH! <333 constant speed is zero acceleration. speed is change of distance/change time Average speed= distance/time motion is the changing ...

*March 4, 2007 by Christina*

**algebra**

tugboat goes 160 miles upstream in 10 hours. The return trip downstream takes 5 hours. Find the speed of the tugboat without a current and the speed of the current. speed of tugboat is speed of the current is

*March 30, 2012 by scott*

**scicnec**

An earth satellite in an elliptial orbit moves with a) slower speed as it ages b) none of the above c) constant speed d) faster speed as it ages Just need to know if my answer or right or wrong. Thanks! :) d

*August 17, 2010 by ant*

**physics**

A 3 kg toy car with a speed of 10 m/s collides head-on with a 2 kg car traveling in the opposite direction with a speed of 3 m/s. If the cars are locked together after the collision with a speed of 4.80 m/s, how much kinetic energy is lost?

*June 26, 2011 by Brittany*

**physics**

A 3 kg toy car with a speed of 10 m/s collides head-on with a 2 kg car traveling in the opposite direction with a speed of 2 m/s. If the cars are locked together after the collision with a speed of 5.20 m/s, how much kinetic energy is lost?

*September 18, 2012 by mk*

**physics**

A 3 kg toy car with a speed of 10 m/s collides head-on with a 2 kg car traveling in the opposite direction with a speed of 2 m/s. If the cars are locked together after the collision with a speed of 5.20 m/s, how much kinetic energy is lost?

*September 18, 2012 by mk*

**physics**

A 3 kg toy car with a speed of 10 m/s collides head-on with a 2 kg car traveling in the opposite direction with a speed of 2 m/s. If the cars are locked together after the collision with a speed of 5.20 m/s, how much kinetic energy is lost?

*September 18, 2012 by mk*

**Physics (Momentum)**

Can anyone please help me with this question? I don't understand why the speed is v m/s. A sport utility vehicle is travelling at a speed of v m/s. If its momentum has a magnitude of 32,800 kg·m/s, what is the SUV's mass? Thanks I know that I have to use the formula p= m*v ...

*May 2, 2013 by Kathy*

**math**

The train slows down uniformly from a speed of 50m/s to a speed of 10m/s in a time of 20sec,During the next 30sec,it accelerates uniformly to a speed of u metres/sec.calculate the retardation from t=0 to t=20?

*May 3, 2013 by Meggy lep*

**math**

Aryan has to travel certain distance from his home at a speed of 5 kilometre hours on his way back to home the speed decreases to 3 kilo metre per hour find his average speed.

*December 21, 2015 by Balram*

**Algebra**

on a canoe trip, Rita paddled upstream (against the current) at an average speed of 2 mi/hr relative to the riverbank. on the return trip downstream (with the current), her average speed was 3 mi/hr. find rita's paddling speed in still water and the speed of the river's ...

*January 14, 2008 by Amber*

**Physics**

a 5 kg block with a speed of 3 m/s collides with a 10 kg block that has a speed of 2 m/s in the same direction. After the collision, the 10 kg block is observed to be traveling in the original direction with a speed of 2.5 m/s. a) what is the speed of the 5 kg block ...

*January 13, 2008 by Sarah*

**Math**

The Danville Epress travels 280mi at a certain speed.If the speed had been increased by 5mph the trip could have been made in 1 hour less time.Find the actual speed.

*February 15, 2011 by Nicole*

**math**

The Danville Epress travels 280mi at a certain speed.If the speed had been increased by 5mph the trip could have been made in 1 hour less time.Find the actual speed.

*February 15, 2011 by Nicole*

**science**

Thank you. I don't know if this one is right- At the speed of 2.5m/s, how many seconnds will it take the kayak to run a 4,500 m course? what is the speed of the kayak in kilometers per hour? speed= 4,500km/2.5h*60min/1 h =270,000/2.5=108,000km/h Thank you Ms. Sue :-)

*March 9, 2011 by Annie*

**physics**

A race car enters a flat 200 m radius curve at a speed of 20 m/swhile increasing its speed at a constant 2 m/s2. If thecoefficient of static friction is .700, what will the speed of thecar be when the car beings to slide?

*October 13, 2011 by holt*

**physics**

An automobile tire has a radius of 0.335 m, and its center moves forward with a linear speed of v = 24.1 m/s. (a) Determine the angular speed of the wheel. (b) Relative to the axle, what is the tangential speed of a point located 0.243 m from the axle?

*July 16, 2013 by katie*

**PHYSICS**

AN AUTOMOBILE TIRE HAS A RADIUS OF 0.330M AND ITS CENTER MOVES FORWARD WITH A LINEAR SPEED OF V= 15.0M/S. a) DETERMINE THE ANGULAR SPEED OF THE WHEEL. B) RELATIVE TO THE AXLE, WHAT IS THE TANGENTIAL SPEED OF A POINT LOCATED 0.175M FROM THE AXLE?

*November 8, 2016 by kassy*

**physics**

A hockey puck moving due east with speed 1.00 m/s collides with an identical puck moving 40 degrees south of west with speed 2.00 m/s. After they collide, the first puck is moving south with speed 1.50 m/s. What is the direction and speed of the second puck?

*September 16, 2010 by Jess*

**physical science**

a yo-yo is swung in a vertical circle in such a way that its total energy KE and PE is constant. At what point in the circle is this speed maximum? A minumum? why? (b) if the yo-yo has a speed of 3 m/s at the top of the circl, whose radius is 80 cm, what is tis speed at the ...

*September 19, 2012 by tracey*

**intermediate algebra**

a cyclist bikes at a constant speed for 19 mile. He then returns home at the same speed but takes a different route. His return trip takes one hour longer and is 24 miles. Find his speed

*November 8, 2016 by maria*

**physics**

A cart starts from position 4 (which is 20m above ground) in the figure below with a velocity of 11 m/s to the left. Find the speed with which the cart reaches positions 1, 2, and 3. Neglect friction. speed at position 1 m/s? speed at position 2 m/s? speed at position 3 m/s? ...

*February 27, 2012 by Jacky*

**Physics**

An attacker at the base of a castle wall 3.82 m high throws a rock straight up with speed 7.10 m/s from a height of 1.45 m above the ground. (a) Will the rock reach the top of the wall? __yes __no (b) If so, what is its speed at the top? If not, what initial speed must it have...

*September 8, 2012 by Emily*

**Physics**

A sky diver of mass 80.0 ks jumps from a slow-moving aircraft and reaches a terminal speed of 50.0 m/s. a) What is the acceleration of the sky diver when her speed is 30.0 m/s? What is the drag force on the diver when her speed is b) 50.0 m/s? c) 30.0 m/s? If you assume drag ...

*March 1, 2007 by Jean*

**Physics ~really need help!~**

1) A 1 kg mass moving at 1 m/s has a totally inelastic collision with a 0.7 kg mass. What is the speed of the resulting combined mass after the collision? 2) A cart of mass 1 kg moving at a speed of 0.5 m/s collides elastically with a cart of mass kg at rest. The speed of the ...

*February 25, 2013 by Isis*

**Algebra**

The boat travels 60 miles to an island and the same 60 miles coming back. Changes in the wind and tide made the average speed on the return trip 3 mph slower than the speed on the way out. If the total time of the trip took 9 hours, find the speed going to the island and the ...

*August 1, 2015 by Scott*

**physics**

A boat’s speed in still water is 1.80 m/s . The boat is to travel directly across a river whose current has speed 1.20 m/s . Determine the speed of the boat with respect to the shore.

*February 9, 2016 by JerkyBerky*

**physics**

starting from reast a boat increases its speed to 4.12 m/s with constant acceleration. (a) what is the boat's average speed? (b) If it take the boat 4.77s to reach this speed, how for has it traveled?

*November 17, 2011 by taylor*

**physics**

Starting from rest, a boat increases its speed to 4.92 m/s with constant acceleration. (a) What is the boat's average speed? (b) If it takes the boat 5.07 s to reach this speed, how far has it traveled?

*August 29, 2012 by stoic-rider77*

**physics**

A horse is running across a field. The horse accelerates at 8.00 m/s2 over a distance of 9.70 m. It runs until its speed is 23.4 m/s and continues at this speed. What was the horse's initial speed?

*September 28, 2016 by lilly*

**physics**

A 56.0-kg skater is traveling due east at a speed of 2.80 m/s. A 77.0-kg skater is moving due south at a speed of 4.40 m/s. They collide and hold on to each other after the collision, managing to move off at an angle south of east, with a speed of vf. Find (a) the angle and (b...

*October 16, 2008 by chris*

**Maths**

The braking distance of a car is directly proportional to te square of it's speed. When the speed is p metres per second, the braking distance is 6m. When the speed is increased by 300%, find (a) an expression for speed of the car (b) the braking distance (c) the % increase in...

*October 21, 2011 by StuartKess*

**physics**

A 59.0-kg skater is traveling due east at a speed of 1.80 m/s. A 61.0-kg skater is moving due south at a speed of 6.20 m/s. They collide and hold on to each other after the collision, managing to move off at an angle south of east, with a speed of vf. Find (a) the angle and (b...

*October 22, 2012 by sammy*

**Physics circular motion**

A speed skater goes into a turn with a 31 meter radius. The skater has a speed of 14 m/s and experiences a centripetal force of 460 n. What is the mass of the speed skater

*December 5, 2014 by Alejandro*

**math 117**

A passenger train can travel 325 mi in the same time a freight train takes to travel 200 mi. If the speed of the passenger train is 25 mi/h faster than the speed of the freight train, find the speed of each. Speed = distance/time Therefore time = distance/speed. Assume the ...

*July 11, 2007 by Diana*

**Physics**

When a small object is launched from the surface of a fictitious planet with a speed of 52.0 m/s, its final speed when it is very far away from the planet is 32.0 m/s. Use this information to determine the escape speed of the planet.

*April 1, 2014 by Ying*

**10th grade Academic Math**

hi can you help me with this problem please, thank you.----------------- If the speed of an experimental car is decreased by 8km/h it completes a 140 km trip in 2 hours more than had it been traveling at its usual speed. Determine its usual speed.

*June 7, 2010 by Neil*

**10th grade Academic Math**

hi can you help me with this problem please, thank you.----------------- If the speed of an experimental car is decreased by 8km/h it completes a 140 km trip in 2 hours more than had it been traveling at its usual speed. Determine its usual speed.

*June 7, 2010 by Neil*

**10th grade Academic Math**

hi can you help me with this problem please, thank you.----------------- If the speed of an experimental car is decreased by 8km/h it completes a 140 km trip in 2 hours more than had it been traveling at its usual speed. Determine its usual speed.

*June 7, 2010 by Neil*

**Intermediate algebra**

Hello, I am kind stuck on this question In the lab you discover a relationship between the temperature of the air and the speed of sound. You find the speed of sound is never lower than 331 m/s and increases by 60% of the current temperature. a. What is the equation from this ...

*November 28, 2011 by Jennifer*

**physics**

a wheelof diameter 0.70 meterolls without slipping. a point at the top of the wheel moves with a tangential speed of 2.0 meter/second. a) at what speed is the axis of the wheel moving? b) What is the angular speed of the wheel?

*March 24, 2014 by Anonymous*

**Calculus**

The fuel efficiency, E, in litres per 100 km, for a car driven at speed v, in km/h is E(v)=1600v/(v^2+6400) a)If the speed limit is 50 km/h, determine the legal speed that will maximize the fuel efficiency. Could someone explain to me why the legal speed is 50 km/h to maximize...

*March 5, 2012 by Jessica*

**math**

a bus takes 12 hours to travel the same distance that an airplane travels in 1.5 hours. the average speed of the airplane ia 120 km per hour faster than five times the average speed of the bus. what is the average speed of the bus? let x represent the speed of the bus speed of...

*November 29, 2006 by aaron*

**Math**

An aircraft flew 3hrs with the wind. The return trip took 4hrs against the wind. If the speed of the plane in still air is 180mph more than the speed of the wind, find the wind speed and the speed of the plane in still air.

*September 27, 2011 by Ingrid*

**physics**

if a stone at the end of a string is whirled in a circle, the inward pull on the stone A) is known as the centrifugal force B) is inversely proportional to the speed of the object C) is inversely proportional to the square of the speed D) is proportional to the speed E) is ...

*May 28, 2012 by star*

**physics - SHM**

Calculate the speed of the pulse from the following: y(x,t) = 2/((x - 3t)^2 + 1) Well the speed of the pulse is given by: y(x,t) = f (x - vt) for a pulse traveling to the right and y(x,t) = f (x + vt) for a pulse traveling to the left but in this case the function is (x - 3t)^...

*April 14, 2007 by COFFEE*

**Physics**

An attacker at the base of a castle wall 3.95 m high throws a rock straight up with speed 5.00 m/s from a height of 1.50 m above the ground. (a) Will the rock reach the top of the wall? (b) If so, what is its speed at the top? If not, what initial speed must it have to reach ...

*September 15, 2014 by Lorine*

**Physics**

An attacker at the base of a castle wall 3.95 m high throws a rock straight up with speed 5.00 m/s from a height of 1.50 m above the ground. (a) Will the rock reach the top of the wall? (b) If so, what is its speed at the top? If not, what initial speed must it have to reach ...

*September 15, 2014 by Lorine*

**Physics**

Starting from rest, a 6.70 kg object falls through some liquid and experiences a resistive (drag) force that is linearly proportional to the velocity of the object. It's measured that the object reaches half its terminal speed at 4.50 s. a) What is the terminal speed for this ...

*July 26, 2012 by Zac*

**physics**

An athlete executing a long jumper leaves the ground at a 27.0 degree angle and travels 7.89 m. What was the takeoff speed? If this speed were increased by just 5.0%, how much longer would the jump be? I came up with a take off speed of 27.4 but the system is saying that is ...

*September 22, 2010 by jason*

**physics**

A girl riding a bicycle with a speed of 5m/s towards northdirection , observes rain falling vertically down. If she increases her speed to 10m/s , rain appears to meet her at 45degree tp the vertical .what is the speed of rain ?

*August 28, 2012 by manish dagar*

**Math**

Marie traveled to work (7km) in 25 minutes. What was her speed? I got 16.8km/h but my teacher said it's 28km/h and I have no idea how he got that. Also, how do you calculate average speed when there's more than one speed? (this is just for the next question)

*June 13, 2016 by Emily*

**MATH**

THE AVERAGE WIND SPEED INCREASED 19 MILES/H FROM 8 AM TO 12 NOON. THE AVERAGE WIND SPEED DECREASED 5 MI MI/H FROM 12 NOON TO 4 PM. AT 4 PM, THE AVERAGE WIND SPEED WAS AT LEAST 32 MI/H. WHAT IS THE MINIMUM VALUE OF THE AVERAGE WIND SPEED AT 8 AM? NEED TO SOLVE AN INEQUALITY ...

*November 30, 2011 by Justin*

**College Physics**

a horizontal speed of 15.8 m/s and a vertical speed 10.0 m/s upward. What is the vertical speed 1.12 s later?

*September 26, 2010 by J*

**Calc One**

The function C(m) = -.41m^2 + 6.7m - 44/ .7m represents Miles Traveled per lb. of CO 2 released as a function of speed(in MPH) for a hyundai Sontana. the domain of this function is [10,90]. A) calculate C'(m) B)find the critical points of C(m). C)Where does C(m) have global ...

*November 6, 2016 by Liz*

**PHYSICS 3**

A solid disk (mass = 1 kg, R=0.5 m) is rolling across a table with a translational speed of 9 m/s. a.) What must the angular speed of the disk be? rad/s d.) The disk then rolls up a hill of height 2 m, where the ground again levels out. Find the translational and rotational ...

*October 20, 2008 by kelsey*

**Physics**

please help me 1)In the movie The avengers, Captain America sees an alien speeder incoming. The speeder passes directly overhead at 3.65m. If he throws his shield straight up with a speed of 7.40 m/s from a height of 1.55 m above the ground (a) will the shied reach the speeder...

*August 24, 2016 by Kevin*

**physicsss**

A Thompson’s gazelle can reach a speed of 13 m/s in 3.0 s. A lion can reach a speed of 9.5 m/s in 1.0 s. A trout can reach a speed of 2.8 m/s in 0.12 s. Which animal has the greatest acceleration?

*October 28, 2010 by Jay*

**physics**

A .50kg ball is rolling on a frictionless surface at a speed of .75m/s. it collides with a second ball with a mass of 1kg which is also moving in the same direction as the first ball with a speed of .38m/s. After the collision the firt ball continues at a reduced speed of .35m...

*March 26, 2011 by Mari*

**math**

a car travels at a constants speed and uses G(x) litres of gas per kilomotre, where x is the speed of the car in kilomotres oer hour and G(x)=(1280+x^2)/(320x) a>if fuel costs 1.29 per litre, determine the cost function C(x)that expresses the cost of the fuel for a 200KM ...

*October 31, 2011 by invy*

**math in distress**

A salesman drove 480 miles from Pittsburgh to Hartford. The next day he returned the same distance to Pittsburgh in half an hour less time than his original trip took, because he increased his average speed by 4 mph find his original speed. Okay... I did it this way...480/2= ...

*July 1, 2015 by toya5*

**physics**

the earthis moving around the sun in a circular orbit of radius 1.5*10^11. it makes one revolution per year.find the angular speed of earth in radian/sec, and the tangential speed of earth using the formula v=r.w , and tangetial speed ?

*April 25, 2010 by mo*

**physics**

a patrol of timing paths each vehicle needs to travel the first half of the distance at a speed of 140 km / h. if the speed limit is 80km / h. which should be the highest average speed of the car in the second half of the section, to avoid being fined?

*October 10, 2010 by liz*

**Physics**

a steel ball drops onto a thick steel plate. its speed just before it hits is 10 m/s and it rebounds with a speed of 9 m/s. what percentage of its kinetic energy did it lose during the collision? what would you expect its speed to be after the second rebound?

*September 6, 2012 by Megan*

**Physics**

A GPS satellite orbits at an altitude of 2.0 x 10^7 m and a speed of 3.9 x 10^3 m/s, Earth’s radius is 6.4 x 10^6 m, and a point at its equator has tangential speed of 460 m/s, By approximately what fraction must the time be adjusted to account for both regular/speed-...

*January 21, 2013 by Katie*

**Science**

What is the distance an object travels per unit of time? It's called the speed Depends on the velocity (speed), if the speed is 10mph, then the object would travel 10 miles (distance) per hour (unit of time). I'm unsure what your answer is saying, because velocity and speed ...

*September 18, 2006 by Ginger*

**Algebra**

During the first part of a trip, a canoeist travels 57 miles at a certain speed. The canoeist travels 13 miles on the second trip at a speed 5 mph slower. The total time for the trip is 5 hrs. what was the speed on each part of the trip? The speed on the first part is? The ...

*April 22, 2012 by Stella*

**Physics**

A dentist causes the bit of a high-speed drill to accelerate from an angular speed of 1.20x10^4 rad/s to an angular speed of 3.14x10^4 rad/s. In the process, the bit turns through 1.92x10^4 rad. Assuming a constant angular acceleration, how long would it take the bit to reach ...

*October 23, 2012 by Sam*

**Physics**

A centrifuge takes 100 s to spin up from rest to its final angular speed with constant angular acceleration. If a point located 8.00 cm from the axis of rotation of the centrifuge moves with a speed of 150 m/s when the centrifuge is at full speed, how many revolutions does the...

*June 24, 2012 by Bloom*

**Physics**

Car A and B are passing each other in different lanes. Car A has an initial speed of 15m/s and is gaining speed at 1.5m/s^2. Car B has an initial speed of 20m/s and is gaining speed at 2.0m/s^2. Find when and where the cars will pass one another and their speeds as they are ...

*February 20, 2008 by Anonymous*

**algebra**

With a tailwind, a bird flew at a ground speed of 3 mi/hr. Flying the same path against the same wind, the bird travels at a ground speed of 1.5 mi/hr. What is the bird's air speed? What is the wind speed?

*February 5, 2012 by tean*

**Algrebra**

with a tailwind, a bird flew at a ground speed of 3 mi/h. Flying the same path against the same wind, the bird travels at a ground speed of 1.5 mi/h. What is the bird's air speed? What is the wind speed?

*January 21, 2014 by Nathan*

**Physics**

A car is driven from point A to B at a constant speed of 25.0 m/s along a straight line, and then back from point B to A at a constant speed of 20.0 m/s. The values of the average speed over the entire trip is?

*January 19, 2010 by Mandy*

**Physics**

An airplane takes off at 9:00 A.M. and flies at 300. km/h until 1:00 P.M. At 1:00 P.M. its speed is increased to 400. km/h, and it maintains this speed until it lands at 3:30 P.M. What is the airplane’s average speed for the entire flight?

*June 16, 2014 by Piper*

**trigonometry**

A Wheel of radius 14in. is rotating 0.5 rad/sec. What is the linear speed v, the angular speed in RPM ( rev per min), and the angular speed in deg/sec?

*April 8, 2015 by Dan*

**physics**

If a runner travels at a speed of 10 m/s for 5 seconds, stops for a short time then continues on at a speed of 8 m/s for 4 seconds. How long was the runner stopped for if his average speed at the end of the trip is 4 m/s.

*February 22, 2011 by mikey*

**physics**

If a car completes a 3.8 mi oval track in 69.7 s, what is the average speed? answer in mph Did the car accelerate? (A.yes the direction of the motion changed or B. yes the speed changed or C. no the speed didn't change)

*June 14, 2011 by alexa*

**waves and optics**

Cherenkov radiation is light emitted by a particle moving through a medium with a speed greater than the speed of light in the medium. (Note: The speed of the particle is not greater than the speed of light in a vacuum.) Consider a beam of electrons passing through water with ...

*May 27, 2012 by jennifer*

**college physics**

A car is driven from point A to B at a constant speed of 25.0 m/s along a straight line, and then back from point B to A at a constant speed of 20.0 m/s. The values of the average speed over the entire trip is?

*January 19, 2010 by Mandy*

**Physics**

Tarzan swings on a 27.0 m long vine initially inclined at an angle of 33.0° with the vertical. (a) What is his speed at the bottom of the swing if he starts from rest?(b) What is his speed at the bottom of the swing if he pushes off with a speed of 3.00 m/s?

*March 10, 2010 by Kelsey*

**Calculus**

The fuel efficiency, E, in litres per 100 km, for a car driven at speed v, in km/h is E(v)=1600v/(v^2+6400) a) determine the legal speed that will maximize the fuel efficiency using speed limit of 50 km/h

*February 24, 2012 by Jake*

**physics**

Tarzan swings on a 34.0-m-long vine initially inclined at an angle of 33.0° with the vertical. (a) What is his speed at the bottom of the swing if he starts from rest? m/s (b) What is his speed at the bottom of the swing if he pushes off with a speed of 5.00 m/s? m/s

*October 10, 2012 by monic*

**physics**

A supersonic jet flying at 137 m/s is accelerated uniformly at the rate of 23.1 m/s2 for 20.0 s. (a) What is its final velocity? (b) The speed of sound in air is 331 m/s. How many times the speed of sound is the plane's final speed?

*October 23, 2012 by miranda*

**Physics**

Which of the following statements correctly describes the changes that occur in a sound wave, as it passes from cool air into warmer air? A) speed,wavelength and frequency all increase B) speed, wavelength increase; frequency decreases C) speed, wavelength increase; frequency ...

*November 28, 2014 by Kiki*

**physics**

a boy walks to a school at a rate of 6km with a speed of 2.5km/h and walks back with a constant speed of 5km/h. his average speed for round trip in km/h is ?

*June 25, 2011 by aleeza*

**physics**

The speed of an automobile increases from 11 m/s to a speed of 47 m/s over a time period of 9.0 seconds. What is the average rate at which the speed of this car is changing during this time period?

*September 2, 2011 by Anonymous*

**science/math**

A car travels up a hill at a constant speed of 45 km/h and returns down the hill at a constant speed of 70 km/h. Calculate the average speed for the round trip.

*September 24, 2011 by Jonathan*

**physics**

If a race car completes a 3 mi oval track in 50 s, what is its average speed? Did the car accelerate? 1. Yes, the speed changed. 2. No, the speed didn’t change. 3. Yes, the direction of the motion changed.

*September 25, 2011 by anon*

**Physics**

A sound wave in a solid has a frequency of 15.0 kHz and a wavelength of 0.333 m. What would be the wave speed, and how much faster is this speed than the speed of sound in air?

*March 4, 2014 by Melanie*

**math**

Jennifer drove at steady speed for 2 hours then reduced speed by 10 mph and drove for another 3 hours what was the initial speed if the total distance was 220 miles?

*January 12, 2016 by Omar*

**Physics**

a train travels the first 30 km of 120 km track with a uniform speed of 30km/h.What should be the speed of train to cover the remaining distance of the track so that its average speed is 60km/h for the entire trip

*June 22, 2014 by Hitesh*

**physics**

A man in a boat moving at constant speed of 60km/h relative to the shore throws an object in the forward direction with a speed of 30km/h. What is the speed of the object as measured by an observer at rest at the shore?

*August 12, 2014 by samson*

**physics**

A man in a boat moving at constant speed of 60km/h relative to the shore throws an object in the forward direction with a speed of 30km/h. What is the speed of the object as measured by an observer at rest at the shore?

*September 2, 2014 by AYANKPELE ASIAGBE*

**Physics, science**

A billiard ball moving with a speed of +4 m/s runs head on into the back of another ball moving with a speed of +2 m/s. After the collision the first ball was measured to be moving with a speed of +2 m/s. Find the speed of the second ball. formula = mivi+m2v2= mivi+m2v2 so far...

*December 18, 2011 by Bassel*

**math please help**

The speed of a passenger train is 8 mph faster than the speed of a freight train. The passenger train travels 310 miles in the same time it takes the freight train to travel 270 miles. Find the speed of each train. What is the speed of passenger train? What is the speed...

*October 24, 2016 by madison*

**physics**

In 1954, Roger Bannister became the first human to run a mile in less than 4 minutes. Suppose that a runner on a straight track covers a distance of 1.00 mi in exactly 4.00 min. 1. What is his average speed in mi/h? 2. What is his average speed in ft/s? 3. What is his average ...

*January 20, 2011 by andrea*