Part I. Do all 8 questions. 5 pts each

1.) _{
}
can be expressed in

- kg m
- kg m/s
- kg m/s
^{2} - kg m
^{2}/s^{2}

2.) A truck at rest at the top of the hill
rolls down
and achieves a speed of 12 m/s at the bottom.
In a second experiment, the same truck has an
intial speed of 5 m/s at the top of the hill. Its speed v_{f}
at the bottom will be:

- 7 m/s
- 8 m/s
- 13 m/s
- 17 m/s

3.) It takes 10 Nm of work to compress an ideal spring 12 cm. How much work does it take to compress it 24 cm?

- 14 Nm
- 20 Nm
- 34 Nm
- 40 Nm

4.) A 2.0 kg particle with total energy
of 6 J is trapped in the potential "well" below. When the particle is at x = 3.5 m, its acceleration is: [hint: calculate the force and use
Newton's 2^{nd} law]

- 1 m/s
^{2} - -1 m/s
^{2} - +3 m/s
^{2} - - 3 m/s
^{2}

5.) When
the m = 2kg block slides down the plane, it reaches a final speed at the bottom of v_{F} =
7.0 m/s. The initial
potential energy dissipated as heat is:

- 0
- 7.0 J
- 15 J
- 49 J

6.) A tennis racket strikes a tennis ball with a force F = F(t) whose graph is shown below:

The total linear momentum change Æp given to the tennis ball is:

- 0
- 5 kg m/s
- 10 kg m/s
- 20 kg m/s

7.) The center of mass of the two particles
below is at x_{ cm} =

- 0 m
- 0.8 m
- 1.2 m
- 1.6 m

8.) Two identical hockey pucks collide on horizontal, frictionless ice.

What must be the final speed v_{f} of the top puck?

- 0.45 m/s
- 1.155 m/s
- 0.1155 m/s
- 0
- I need v
_{o}to answer this question

1.) A small roller coaster of mass m has an initial horizontal speed of 4.0 m/s at point A at the top of the hills. It rolls down over the smaller hill and coasts horizontally a distance L and comes to a stop. Calculate: [You must start with a physical law and then proceed logically, step-by-step, to obtain full credit. Don't forget units in your answer.]

- the roller coaster's speed at point C (10)
- how
far it rolls (L) on the horizontal surface which has a coefficient of kinetic friction of
*m*= 0.2. (20)

2.) A bullet of mass m_{1} and horizontal speed v_{o}
strikes a stationary block of mass m_{2}. Calculate (in symbols): [You must start with a physical law, write complete equations
and include every step in your answer to get full credit.]

- the final speed of the bullet and block in terms of m
_{1}, m_{2}, and v_{o}. (10) - the ratio of
_{ }in terms of m_{1}and m_{2}(10) - Which kinetic energy is larger KE intial or KE final? Where did the difference in kenitic energy go? (10)

KE initial = total KE of system of m_{1} + m_{2}
before bullet strikes m_{2}

KE final = total KE of system of m_{1} + m_{2} after bullet
comes to rest in m_{2.}