a. A mechanic pushes a 2.8 103 kg car from rest to a speed of v, doing 5500 J of work in the process. During this time, the car moves 26.0 m. Neglecting friction between car and road, find each of the following.
(a) the speed v
b. A 7.0 kg bowling ball moves at 2.00 m/s. How fast must a 2.60 g Ping-Pong ball move so that the two balls have the same kinetic energy?
c. A crate of mass 12.5 kg is pulled up a rough incline with an initial speed of 1.50 m/s. The pulling force is 100 N parallel to the incline, which makes an angle of 16.0° with the horizontal. The coefficient of kinetic friction is 0.400, and the crate is pulled 4.30 m.
How much work is done by gravity?
How much mechanical energy is lost due to friction?
How much work is done by the 100 N force?
What is the change in kinetic energy of the crate?
What is the speed of the crate after being pulled 4.30 m?
d. On a frozen pond, a 7 kg sled is given a kick that imparts to it an initial speed of v0 = 2.4 m/s. The coefficient of kinetic friction between sled and ice is µk = 0.10. Use the work-energy theorem to find the distance the sled moves before coming to rest.