PHY 1151

Second Hour Exam

June 26, 2003

Statistics:

High: 94

Mean: 67

Low: 39

**1.** A 60-kg pilot comes out of a dive by flying along an arc of radius
800 m with a speed at the bottom of 120 km/h. What is her apparent weight at
the bottom of the arc?

**2.** At the end of an air track, a spring with spring constant of 50 N/m
is compressed 0.10 m.

a) How much potential energy is stored in the spring?

A 0.200-kg air track glider is placed next to the compressed spring. The spring
is released. The glider looses contact with the spring when the spring returns
to its equilibrium position.

b) What is the speed of the glider as it leaves the spring?

3. Consider a totally ** in**elastic collision between two gliders
on an air track.

The two collide and stick together and move off with a common velocity v

Glider #1 has a mass of 250 g (or 0.250 kg) and moves to the right with an initial speed of 50 cm/s (or v

Glider #2 has a mass of 200 g (or 0.200 kg) and moves to the

a) Find that common, final velocity v

b) What is the total kinetic energy

c) What is the total kinetic energy

**Concept Questions:**

**i.** What is __centripetal__ force?

__Centripetal force__ is the ** net force**
that acts on an object as it moves in a circle; it is directed toward the

Work is the product of a force

Kinetic energy is energy of

Conservation of momentum is connected with Newton’s