Number of results: 30,492
find the average of a block being propelled propelled by an elastic band. very sorry to disturb Mr bobpurlsey again. i am very thankful to you replies. the only problem that lies in the answer is that i haven't been taught hooke's law in Grade 11. which indicates 1/2kx^2 i ...
Wednesday, June 13, 2007 at 7:49pm by james
sorry mr bob purlsey again to annoy you. so i did all my calculations and read about hooke's law yesterday and presented to my teacher. however i was not allowed to used hooke's law because we haven't learned it yet and i did not know how to connect potential energy to force ...
Thursday, June 14, 2007 at 11:16pm by physics(sorry)
a 400 g rubber ball is dropped a vertical distance of 12 m onto the pavement. it is in contact with the pavement for 0.01 s and rebounds to a height of 10 m. what is the total change in momentum? what average force is exerted by the pavement on the ball? this is what i have so...
Thursday, June 26, 2008 at 10:11am by laur
a 120kg ball moving at 18m/s strikes a wall perpendicularly and rebounds straight back at 12m/s. after the initial contact, the centre of the ball moves 0.27cm closer to the wall. Assuming uniform deceleration, show that the time of the contact is 0.00075s. How large an ...
Sunday, September 30, 2007 at 5:31am by kale
A 2.0 g bullet leaves the barrel of a gun at a speed of 300m/s. (a) Find its kinetic energy. (b) Find the average force exerted on the bullet by expandin gases as the bullete moves the length of the 50 cm long barrel. I did (a), but I am not sure if it is correct. I tried (b...
Sunday, October 21, 2007 at 9:40pm by Anonymous
A ping pong ball (m= 6g) bounces off a table. Before striking the table the ball has a velocity of 4m/s in a direction pheta below the x-axis. It leaves the table with the same speed moving in a direction pheta above the x axis. What impulse does the table exert on the tennis ...
Monday, October 22, 2007 at 4:11am by Anonymous
A 0.15 kg baseball is pitched with a speed of 35 m/s (77 mph). When the ball hits the catcher's glove, the glove moves back by 2.7 cm (1.08 in.) as it stops the ball. Assuming a constant acceleration of the ball, what was the average force applied by the catcher's glove?
Monday, October 22, 2007 at 9:54pm by Dante
A catcher “gives” with the ball when he catches .15 kg baseball moving at 25 m/s. (a) If he moves his glove a distance of 2.0 cm, what is the average force acting on his hand? (b) Repeat for the case in which his glove and hand more 10 cm.
Thursday, October 25, 2007 at 12:14am by Anonymous
The average velocity of the ball between first contact with the glove and when it stops is 25/2 = 12.5 m/s. The time that the ball is decelerated is T = D/12.5 m/s, where d is the distance that the glove moves backwards. The average force is given by the momentum law (avg. ...
Thursday, October 25, 2007 at 12:14am by drwls
A 9 kg lead brick falls from a height of 1.8 m. a) Find the momentum as it reaches the ground. b) What impulse is needed to bring the brick to rest? c) The brick falls onto a carpet 2.0 cm thick. Assuming the force stopping it is constant, find the average force the carpet ...
Wednesday, November 7, 2007 at 1:02pm by Jayd
a)You seem to be using g = 10 m/s^2 instead of the actual 9.8 m/s^2. If you are going to carry three significant figures, you should use a g that is that accurate. You also do not seem to have used h_c of 100 m in your g h calculation. b)To get the highest speed, you need ...
Wednesday, November 14, 2007 at 8:02pm by drwls
A car is driven at a constant speed of 21 m/s (76km/h) down a road. The car's engine delivers 52 kW of power. Calculate the average force of friction that is resisting the motion of the car. My thinking: Convert 52 kW to 5200 W. Force of friction = force applied because there ...
Wednesday, November 14, 2007 at 11:38pm by Einstein
Since Work = Force x Distance, Power = Force x Velocity Average force = Power/Velocity = (52,000 kg m^2/s^3)/(21 m/s) = 2476 N
Wednesday, November 14, 2007 at 11:38pm by drwls
An archer puts a 0.28 kg arrow to the bow string. An average force of 200 N is exerted to draw the sting back 1.1 m. a) Assuming no frictional loss, what speed does the arrow leave the bow? b) If the arrow is shot straight up, how high does it rise? My thoughts: KE = 1/2mv^2. ...
Friday, November 16, 2007 at 5:31pm by Einstein
8. What average force is needed to accelerate a 7.00-gram pellet from rest to 125 m/s over a distance of 0.800 m along the barrel of a rifle?
Monday, November 19, 2007 at 4:16pm by beckii
Okay I only need help with part (c), but I'll put down the whole problem. a. What impulse occurs when an average force of 10 N is exerted on a cart for 2.5 s? I got 25 N x S (Newtons-Seconds) b. What change in momentum does the cart undergo? I got 25 kg x m/s. c. If the mass ...
Monday, November 19, 2007 at 10:57pm by Emily
What average force is required to stop an 1100-kg car in 8.0 s if it is traveling at 95 km/h? i got the answer to be 13062.5 N. i don't think that's right...
Wednesday, November 21, 2007 at 5:57pm by beckii
First convert kg/h to m/s 95 km/h = (95000 m/h)/(3600) s/h = 26.4 m/s Force x Time = momentum change = 1100*26.4 = 2.90*10^4 kg m/s Divide that by the time interval (8.0s) to get the average force in Newtons
Wednesday, November 21, 2007 at 5:57pm by drwls
physics: BOB or DRWLS follow up question
What average force is required to stop an 1100-kg car in 8.0 s if it is traveling at 95 km/h? i understand what you both did, but why can't you use the V = Vo + at equation and solve for acceleration there and use that in the EF = ma equation?
Wednesday, November 21, 2007 at 8:40pm by beckii
physics: BOB or DRWLS follow up question
Sure. a= averageforce/m Then solve for average force. Same equation.
Wednesday, November 21, 2007 at 8:40pm by bobpursley