# Homework Help: Science: Physics

## Recent Homework Questions About Physics

Physics
A cardboard box of unknown mass is sliding upon a mythical frictionless surface. The box has a velocity of 4.56 m/s when it encounters a bit of friction. After sliding 0.700m, the box has a velocity of 3.33 m/s. What is the coefficient of friction of the surface? Am I right to...

Physics
A football is kicked at ground level with a speed of 17.7 m/s at an angle of 39.8 ∘ to the horizontal. How much later does it hit the ground? Answer=> t=_____ s Express your answer using three significant figures and include the appropriate units.

Physics
Problem: A person has a reasonable chance of surviving an automobile crash if the deceleration is no more than 30 "g's. Part A: Calculate the magnitude of the force on a 71-kg person accelerating at this rate. Answer=> F= 2.09x10^4 N Part B: What distance is traveled if ...

physics
A train travelling at 30km/h stops when it's brakes are applied. The train suffers a deceleration our 2m/s. @. How long does the train take to come to rest? b) what is its final velocity?

physics
a circular wheel rotate 200 nos. of revolution in 30 seconds. find its angular velocity

physics
What is the angle between A and B vectors for which A+B=A-B ?

physics
A. how long will it take for a 55.0 kg steel brick to fall 75 meters on earth. A. how far from the base will a 55.o kg steel brick to land,(horizontally) if it dropped a vertical distance of 75 meters on earth, and what is its velocity just before it hits the ground?

Physics
A 0.50-kg mass is placed on the end of a vertical spring that has a spring constant of 75 N/m and eased down into its equilibrium position. (a) Determine the change in spring (elastic) potential energy of the system. PEs=1/2kx^2=1/2(75)(0.5)^2=9.375 (b) Determine the system...

physics
Explain why helicopters need 2 rotors to fly in a straight line. Talking about centripetal force.

physics
Explain why helicopters need 2 rotors to fly in a straight line.

physics
How does a washing machine's 'spin cycle' expel water from clothes?

Physics
A soccer player kicks a ball at an angle 45degree with an initial speed of 20m/s,assuming that the ball travels in a vertical plane. Calculate (a) The time at which the ball reaches the highest point. (b) The maximum height reached. (c) The horizontal range of the ball and (d...

Physics
What is the net force required to accelarate a 2000kg car to 6m/sec us equation F=ma

physics
a cannon of mass 400kg fires a shell of mass 20kg. if the shell leaves the cannon at 300ms^-1, with what velocity does the cannon recoil? an a- particle is emitted from a polonium nucleus at a speed of 1.8 x 10^7 ms^-1. the relative masses of the a- particle and the remaining ...

physics
What is mean by 28degree east of north

Physics Equilibrium
A table is supported against a wall forming an angle with the vertical. The coefficient of static friction between the table and the floor is (μe). The frictional force of the wall on the board may be neglected. Find an expression for the maximum value that the angle can take...

physics
A panel is supported on supports a and b. A 60-kg person walks on the board from point a. Despise the deformation of the table A) find its expression for the magnitude of the force exerted by each support in function x of the person B) in what position will the person be found...

physics
A panel is supported on supports a and b. A 60-kg person walks on the board from point a. Despise the deformation of the table A) find its expression for the magnitude of the force exerted by each support in function x of the person B) in what position will the person be found...

Physics
A table is supported against a wall forming an angle with the vertical. The coefficient of static friction between the table and the floor is (μe). The frictional force of the wall on the board may be neglected. Find an expression for the maximum value that the angle can take...

Physics
A force of 1500 N (pull) is applied to a 200-kg crate at an angle of 20 degrees above horizontal. The coefficient of static friction is .65 and the coefficient of kinetic friction is .43. Does the crate move? If so, what is its acceleration?

Physics
What Is Simple Harmonic Motion (SHM)?

physics
an annular ring starts from rest and rolls without sliding down a hill from a height of 22.5m. it has an outer radius from 1.0 m and an inner radius of 0.50m. if the moment of inertia of an annular ring in I=1/2M(ro^2 + ri^2), what is th elinear velocity of the ring when it ...

physics
a 50 kg box sits on a scale in an elevator. the scale reads 400N. what is the acceleration of the elevator? (magnitude and direction)

Physics
A block slides down a frictionless 3m long inclined plane making 10 degrees with the horizontal. The block starts from rest. Find acceleration of the block and its speed at the bottom.

Physics
A dart is loaded into a spring-loaded toy dart gun by pushing the spring in by a  distance d. For the next loading?the spring is compressed a distance d/3. How much  work is required to load the second dart compared to that required to load the first? A)nine times as much ...

physics
a 1.0 m long rope with a mass on one end swings in a horizontal circle such that the speed of the mass is 1.5m/s. what is the period of motion?

physics
a large block with a madd of 5kg sits on top of a steep, frictionless hill, which has a height of 45m. what is the velocity of the block by the time it reaches the bottom of the hill?

Physics
A dart is loaded into a spring-loaded toy dart gun by pushing the spring in by a  distance d. For the next loading?the spring is compressed a distance d/3. How much  work is required to load the second dart compared to that required to load the first? A)nine times as much ...

physics biology chemistry and ict
WHAT ARE THE ALLOTROPES OF ANTIMONY

Physics
Maximum height of the stone above the ground

Physics
The Speed Of A Train Is Reduced From 80km/h To 40km/h In A Distance Of 500m On Applying The Brakes (I)how Much Further Will The Train Travel Before Coming To Rest (II)assuming The Retardation Remain Constant,how Long Will It Take To Bring The Train To Rest After The ...

physics
Two forces act on an object. one has a magnitude of 4N in the y axis and the other has a 4N and is pointing 30 degrees below the posive x axis. what is the magnitude of the net force acting on the object?

Physics
A 6.2 g bullet is fired into a 2 kg ballistic pendulum. The bullet emerges from the block with a speed of 281 m/s, and the block rises to a maximum height of 15 cm . Find the initial speed of the bullet. The acceleration due to gravity is 9.8 m/s 2 . Answer in units of m/s.

physics
Una tabla esta apoyada contra un pared formando un ángulo con la vertical. El coeficiente de roce estatico entre la tabla y el piso es ( μe ). La fuerza de roce de la pared sobre la tabla puede despreciarse. Encuentre una expresión para el máximo valor que puede tomar el...

Physics
A steel cable of cross sectional area 2.5 cm^2 supports a 1000kg elevator. The elastic limit of the cable is 3 x 10^8 Pa. If the stress in the cable is not to exceed 20 percent of the elastic limit, then find the maximum upward acceleration of the elevator

physics
Andy is waiting at the signal. As soon as the light turns green, he accelerates his car at a uniform rate of 8.00 meters/second2. What is the displacement of Andy’s car after 30.0 seconds?

physics
Una tabla esta apoyada contra un pared formando un ángulo con la vertical. El coeficiente de roce estatico entre la tabla y el piso es ( μe ). La fuerza de roce de la pared sobre la tabla puede despreciarse. Encuentre una expresión para el máximo valor que puede tomar el...

physics
A positive charge with Q1= +210-6 C and a negative charge Q2 = -1×10-6 C are located at an equal distance 0.1m from the origin (see below). A third charge Q3=+110-6C is located at the origin. Calculate the magnitude of the net force exerted on charge Q3 Calculate the ...

physics
A 2 kg block with initial velocity +2m/s collides with a stationary 6 kg block with initial velocity 0m/s on a frictionless surface. After the collision, the 2 kg block is moving at –1 m/s and the 6kg block is moving to the right at +1 m/s. Show that the total momentum is ...

physics
A 100 kg car is traveling at 20m/s over the top of a circular hill as shown below. The radius of the circle is 200 m. What force does the ground exert on the car at the top of the hill? After reaching the top of the hill, the car descends a vertical distance of 20 m. What is ...

physics
A 2 kg block is being pulled by a rope with a tension of 3N at an angle of 45Â° as shown. The coefficients of friction are Î¼k=0.4 and Î¼s=0.5. Does the block slide or not?

physics
A 0.035 kg spherical oil droplet has charge of +1×10-7C. A uniform electric field is acting upwards as shown below. What strength of electric field is required to make the sphere float in the air without moving?

physics
A 1000 kg car is initially at rest. If the motor does 10,000J of work on the car, what is the car’s final speed? (Neglect friction, and assume that the car is on level ground.)

Physics
A book with a mass of 1350 g is sitting on a desk. The ukf between the book and the desk is .45 and the ukf between the book and the desk is .30. a. how much horizontal force is required to start the book moving across the desk? b. Once it starts moving, what is the ...

physics
A 5kg block has an initial velocity of 15 m/s and is sliding along a surface with friction. Eventually the block comes to rest. what is the change in thermal energy of the block and the surface ?

Physics
A solid, uniform, frictionless cylindrical reel of mass M = 3.00 kg and radius R = 0.400 m is used to draw water from a well.? A bucket of mass m = 2.00kg is attached to a cord that is wrapped around the cylinder. (a) Find the tension T in the cord and acceleration a of the ...

Physics
Assume the sleigh and horse pulling it are on a level, horizontal surface. Given: mass of sleigh 475 kg / force of horse pulling sleigh 1.5×10^5 / coef. of kinetic friction .15 / coef. of static friction .20 a.) What is the normal force of the sleigh and its passengers? b.) ...

Physics
How to get the equivalent resistance in this figure -----------r2------- | | | Battery. R1 R3 | | | -----------R4------ Values: R1= 90 R2= 50 R3= 40 R4= 20

Physics
A 1750 kg van is travelling down a 10 degrees inclined road at a speed of 6 m/s. If the driver brakes suddenly causing the wheels to lock, determine the distance L his tyres will skid on the road. The coefficient of kinetic friction between the wheels and the road is 0.5. (a) ...

Science physics
what will be the acceleration due to gravity at up planet whose mass is 8 times the mass of the earth and whose radius is twice that of the earth? g=10

Physics
A carnot’s engine with air as working substance is initially at 3270C and pressure of 12 atmospheres. The volume is one litre to start with. The expansion or compression ratio is 1:6. Find the lowest temperature and efficiency. (γ= 1.4)

Physics
A 16-g mass is moving in +x direction at 30 cm/s while a 4-g mass is moving in the -x direction at 50 cm/s. they collide head-on and stick together. Find their velocity after collision?

physics
a stone that is thrown near the surface of the earth. There is no air resistance. Position increases in the up direction. The initial velocity is 30 m/s at 30 degrees above the horizontal. what is the velocity when the stone reaches its maximum height ? what is the ...

Physics
arnot’s engine with air as working substance is initially at 3270C and pressure of 12 atmospheres. The volume is one litre to start with. The expansion or compression ratio is 1:6. Find the lowest temperature and efficiency. (γ= 1.4)

Physics
A 15 ft plank of mass 50 kg is laid across two ladders. The ladders are 5 ft apart, and the plank is laid such that 5 ft of it hang off at each end. You have a mass of 90 kg. (a) How far out past the ladder can you walk before it gets dangerous? I tried doing m1r1=m2r2 (33.33...

Physics
1. The figure shows a 100-kg block being released from rest from a height of 1.0 m. It then takes 0.53 s for it to reach the floor. What is the mass m of the block on the left? There is no friction or mass in the pulley, and the connecting rope is very light. A) 16 kg B) 14 kg...

physics
A car's internal combustion engine can be modeled as a heat engine operating between a combustion temperature of 1500∘C and an air temperature of 20∘C with 30% of the Carnot efficiency. The heat of combustion of gasoline is 47 kJ/g. Q) What mass of gasoline is burned to ...

physics
a force of 400 N at an angle of 15 degrees above horizontal is needed to pull a 180 kg trunk across the floor at constant speed. what is the coefficient of kinetic friction between the trunk and the floor

Physics
A force of 400 N at an angle of 15 degrees above the horizontal is needed to pull a 180 kg trunk across the floor at constant speed. What is the coefficient of kinetic friction between the trunk and the floor?

Physics
1. The figure shows a 100-kg block being released from rest from a height of 1.0 m. It then takes 0.53 s for it to reach the floor. What is the mass m of the block on the left? There is no friction or mass in the pulley, and the connecting rope is very light. A) 16 kg B) 14 kg...

Physics
A tennis ball is released at 30 degrees. It reaches max height of 20 ft find initial speed

Physics
Two point sources emit sound waves of 1 m wavelength. The sources are pointed at each other. The sources, 2 m apart, emit waves which are in phase with each other at the instant of emission. a) Where, along the line between the sources are the waves out of phase with each ...

Physics
if a molecules in a solid has a temp of T = hf/2k then what would be the average energy of vibration 1) 0.88kT 2) 0.47kT 3) 0.62kT 4) 0.31kT

Physics
if a molecules in a solid has a temp of T = hf/2k then what would be the average energy of vibration

Physics
A solid weighs 6.4 kg in air and 5.6 in water. Find the density of the solid

Physics
A child is playing with a remote-controlled racecar on the fire escape of a sixth-floor apartment. An accidental turn sends the car through the railing and over the edge of the fire escape. Explain why the time it takes for the car to fall does not depend on the speed the ...

physics
A wheel starting from rest is uniformly accelerated with alpha=4 rad/seconds square for 10 seconds. It is then allowed to rotate uniformly for the next two seconds and is finally brought to rest in the next 10 seconds. Find the total angle rotated by the wheel

physics forces/kinematic
What does it mean that 1) A body can have zero acceleration but still in motion. 2) A body can have zero velocity but it's also accelerating. I don't really understand this two points, please explain it to me, thks!

Physics
Is screw a modified inclined plane?

physics
The coefficient of kinetic friction for wood on wood is o.55. The coefficient of kinetic friction for wood on wood is 0.68. For a 3.5kg wood block being pulled horizontally: a. what is the pull force needed to start the wood block moving on a wood floor? b. how hard would you ...

Physics
A non-homogeneous trunk, 5 meters long and 100 kilograms mass is in equilibrium and is hung at the ends by two strings; One form an angle of 37 degrees and the other an angle of 53 degrees, both with the horizontal. Determine the location of the center of mass of the trunk and...

Physics
A cheeta can run with a speed of 29 m/s. Determine the distance travelled by a running cheetah in 8.6 s. D= 29/8.6 = 3.3s

A 33-N force acing due north and a 44-N force acting at 30 degrees act concurrently on point P. What is the magnitude and direction of a third force that produces equilibrium at point P?

Physics
A shopper exerts a force on a cart of 64N at an angle of 30° below the horizontal. a.) How much force pushes the cart in a forward direction? b.) How much force pushes the cart against the floor?

Physics
An ice skater with a mass of 60.0kg is moving at 20.0 m/s coasts to a halt in 2.00×10^2m on a smooth ice surface. What is the coefficient of friction between the ice and the skates?

Physics
A row of seats is parallel to a stage at a distance of 8.70 m from it. At the center and front of the stage is a diffraction horn loudspeaker that has a width of 7.50 cm. The speaker is playing a tone at a frequency of 9600 Hz . The speed of sound is 344 m/s. a. What is the ...

physics
A golfer tees off and hits a golf ball at a speed of 31 m/s and at an angle of 35 degrees. What is the horizontal velocity component of the ball? Round the answer to the nearest tenth of a m/s.

work and energy PHYSICS
A particle is projected vertically upwards from a point O on horizontal ground which reaches the maximum height Q. What is the energy associated at O and Q?

Physics
What is the work done when a force of 30Newtons moves through a distance of 20Meters?

Physics
The kiloton, which is used to measure the energy released in an atomic explosion, is equal to 4.2 ✕ 1012 J (approximately the energy released in the explosion of 1000 tons of TNT). Recalling that 1 kilocalorie of energy raises the temperature of 1 kg of water by 1°C and ...

Physics
The drawing shows a collision between two pucks on an air-hockey table. Puck A has a mass of 1.5 kg and is moving along the x axis with a velocity of +5.5 m/s. It makes a collision with puck B, which has a mass of 3.2 kg and is initially at rest. The collision is not head-on. ...

Physics
A space station, in the form of a wheel 197 m in diameter, rotates to provide an “artificial gravity” of 2.5 m/s2 for persons who walk around on the inner wall of the outer rim. The rate of the wheel’s rotation in revolutions per minute that will produce this effect is ...

Physics - studying for finals
(a) Write the expression for y as a function of x and t in SI units for a sinusoidal wave traveling along a rope in the negative x direction with the following characteristics: A = 5.00 cm, λ = 75.0 cm, f = 5.00 Hz, and y(0, t) = 0 at t = 0. (Use the following as necessary: x...

Physics - studying for finals
(a) Write the expression for y as a function of x and t in SI units for a sinusoidal wave traveling along a rope in the negative x direction with the following characteristics: A = 5.00 cm, λ = 75.0 cm, f = 5.00 Hz, and y(0, t) = 0 at t = 0. (Use the following as necessary: x...

physics
A 3.4 kg plant hangs from the bracket shown in the figure. The bracket has a mass of 0.65 kg , and its center of mass lies 9.0 cm from the wall. A single screw holds the bracket to the wall. Find the horizontal tension force in the screw. Hint: Imagine that the bracket is ...

physics
the terminal velocity of a tennis ball is about 21 m/s. a tennis ball is dropped from a hot air balloon. how fast will it be moving after falling for 10 s? 21m/s, 77m/s, 9.8m/s, or 98m/s.

Physics
Not sure where to begin with this question--any help appreciated! Two kids sitting on opposite sides of a small lake use sticks to beat the surface of the water at a frequency f=1.5 Hz. They notice that a standing wave pattern develops between the points where they are ...

Physics
If the torque required to loosen a nut that is holding a flat tire in place on a car has a magnitude of 31 N · m, what minimum force must be exerted by the mechanic at the end of a 24 cm-long wrench to loosen the nut? Answer in units of N

physics
experiencing a constant horizontal 1.10 m/s wind, a hot air balloon ascends from the launch site at a constant vertical speed of 2.70 m/s. at a height of 202 m, the balloonist maintains constant altitude for 10.3 s before releasing a small sandbag. how far from the launch site...

Physics
How many kilograms of water can be evaporated at 100 degrees Celsius by the combustion of 470 litres of fuel oil whose heat of combustion is 37 MJ/Litre

PHYSICS
A child (25 kg) walks along a 4 m plank of uniform density (m=8kg) that is laying with one end extending 1 m off the end of a dock. 1. Where is the ceanter of mass located in the plank? 2. What is the magnitude of the torque of the plank about the edge of the dock? 3. How far ...

Physics
You exert a force of 200 N at an angle of 15 degrees above horizontal to pull a 10 kg box across the floor at constant velocity. If the coefficient of kinetic friction between the box and the floor is 0.42, what is the acceleration of the box?

Science physics
How would the voltage output be affected if the armature is made to spin faster?

physics
A 1.6-kg block is attached to the end of a 2.0-m string to form a pendulum. The pendulum is released from rest when the string is horizontal. At the lowest point of its swing when it is moving horizontally, the block is hit by a 10-g bullet moving horizontally in the opposite ...

Physics
If 32s is required for an object to reach maximum height, what will be the time for an object to come back to its initial position? is it 32sec or -32 sec since it's traveling downwards???

Physics
In projectile motion the acceleration at the highest point of curved motion is___. a. 0 b. g c. undefined d. –g Which is true about an object was dropped from a 5 storey building? a. initial velocity is zero b. acceleration is equal to –g c. displacement is negative d. All...

Physics
How long does a car with an acceleration of 2.0 m/s2 take to go from 10 m/s to 30 m/s a. 3 m b. 6 m c. 18 m d. 36 m

physics
how much work is done if a force of 12N moves an object a distance of 5m

Physics
consider the circuit in the figure. find the current in the 13 ohm resistor. Answer in units of A

Physics
A child of mass 30 kg stands beside a circular platform of mass 95 kg and radius 2.4 m spinning at 2.3 rad/s. Treat the platform as a disk. The child steps on the rim. a) What is the new angular speed? b) She then walks to the center and stay there. What is the angular ...