Author Question: A block is pushed across a rough horizontal surface from point A to point B by a force (magnitude P ... (Read 122 times)

sam.t96 · **on:** Jul 28, 2018

A block is pushed across a rough horizontal surface from point A to point B by a force (magnitude P = 5.4 N) as shown in the figure. The magnitude of the force of friction acting on the block between A and B is 1.2 N and points A and B are 0.5 m apart. If the kinetic energies of the block at A and B are 4.0 J and 5.6 J, respectively, how much work is done on the block by the force P between A and B?

a.
2.7 J

b.
1.0 J

c.
2.2 J

d.
1.6 J

e.
3.2 J

Question 2

The two masses in the figure are released from rest. After the 3.0-kg mass has fallen 1.5 m, it is moving with a speed of 3.8 m/s. What is the change in mechanical energy done on the system during this time interval by the frictional force on the 2.0 kg mass?

a.
12 J

b.
17 J

c.
20 J

d.
8.0 J

e.
28 J