1) A 6 kg box is pulled across a rough floor by a rope. There is a friction betw

Question

1) A 6 kg box is pulled across a rough floor by a rope. There is a friction between the box and the floor. The tension in the rope is T = 5N. Consider a time interval during which the box moves a distance of 2m, and its velocity is decreasing from 1.5 m/s to 1.0 m/s.

a) How much work is done by the rope

b) Calculate the work done on the box by friction

2) A puck of mass 1 kg collides with a wall. The puck will explode if hit with a force greater than 15N. Before the collision the pucks velocity is 10 m/s. After the collision the pucks velocity is -10 m/s. Assume a constant force is applied to the puck during the collision.

a) What is the shortest time interval over which this puck could have been hit such that it did not explode?

Explanation / Answer

2) A puck of mass 1 kg collides with a wall. The puck will explode if hit with a force greater than 15N. Before the collision the pucks velocity is 10 m/s. After the collision the pucks velocity is -10 m/s. Assume a constant force is applied to the puck during the collision.

a) What is the shortest time interval over which this puck could have been hit such that it did not explode

Change in momentum is m(v2-v1) = 1(-10-10) = -20 kg m/s

Force max = 15 N

= rate of change of momentum = 20/t t = 20/15 = 1.3333 seconds (min)

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.