1. Which of the following is a conservative forces and has a corresponding potential energy?
a) weight b) normal c) friction d) centripetal e) all forces listed here
________________________________________________________________________________________
2-6. A 3 kg crate slides frictionlessly down a ramp through a vertical distance of 12 m onto a horizontal frictionless surface as shown in Figure 1. The ramp is tilted at 30 degrees above the horizontal.
2. At the foot of the ramp the speed of the crate is _____ m/s.
a) 4.9 b) 470 c) 235 d) 21.7 e) 15.3
3. As the crate slides down the ramp its
a) mechanical energy increases. b) mechanical energy is not conserved.
c) potential energy changes into kinetic energy. d) potential energy increases.
e) kinetic energy changes into potential energy.
4. The crate then collides with a spring (k = 200 N/m) on the horizontal surface and compresses it a maximum distance of _____ m.
a) 1.88 b) 3.53 c) 0.28 d) 0.85 e) 0.53
5. If a force of kinetic friction acted on the crate as it slid down the ramp, the velocity at the bottom would have been _____ that in the frictionless case.
a) larger than b) smaller than c) the same as
6. If the ramp was tilted at 45 degrees rather than 30 degrees as the crate slid frictionlessly through the vertical distance of 12 m, the velocity at the bottom would have been _____ .
a) smaller b) the same c) greater
________________________________________________________________________________________
7-8. A 38 kg student on a 2 kg skateboard rolls frictionlessly along a horizontal sidewalk on the Wright State campus at 1.8 m/s without pushing on the ground.
7. Someone drops a 5 kg winter coat from an overhead window that the skateboarder catches. The speed of the skateboarder after catching the coat is __________ m/s.
a) 1.60 b) 1.40 c) 2.22 d) 2.03 e) 1.80
8. For how many seconds must a horizontal 17 N force be exerted on the coatless skateboarder to raise his speed from 1.8 to 2.7 m/s?
a) 4.2 b) 4.8 c) 6.4 d) 0.8 e) 2.1
_________________________________________________________________________________________
9. A 60 kg and an 80 kg astronaut are "floating" at rest in outer space. One astronaut shoves the other away and the 60 kg astronaut is found to have a speed of 2.3 m/s. The speed of the 80 kg astronaut must be _____ m/s.
a) 3.1 b) 2.0 c) 0 d) 2.3 e) 1.7
10. Within the month we will be saying:
a) Happy Fourth of July! b) MERRY CHRISTMAS! c) Happy Easter!
d) Happy May Day! e) Happy Ground Hog Day!
11. Two objects experience a perfectly elastic collision. Which properties need not be the same before and after the collision?
a) particle velocities b) relative velocity c) total momentum d) total kinetic energy
12. A 1 kg puck sliding on a horizontal frictionless surface in the +x direction with a velocity of +4 m/s "rear ends" a 2 kg puck with a velocity of +3 m/s. After an elastic collision, the 2 kg puck has a velocity of +3.67 m/s and the 1 kg puck has a velocity of _____ m/s.
a) +4.67 b) +3.67 c) -4.67 d) -2.67 e) +2.67
13. Three students sit in a long thin canoe. A 75 kg student sits in the middle, a 60 kg student sits 1.5 m in front of her, and a 55 kg student sits 2 m behind her. Assuming the canoe is massless, where is the center of mass of the student-canoe system with respect to the 75 kg student?
a) 0.17 m in front b) 0.25 m behind c) 0.11 m in front d) 0.11 m behind
e) 0.17 m behind
14. Which of the following physical quantities does not have S.I. units of kg m2/s2?
a) torque b) momentum c) work d) potential energy e) kinetic energy
15. A person weighing 800 N stands with one foot on one bathroom scale and the other foot on a second bathroom scale.
a) Each scale always reads 400 N.
b) If one scale reads 500 N, the other must read 300 N.
c) One of the scales must read 800 N.
d) Each scale always reads 800 N.
e) None of these answers can be true.
16. A seesaw consists of a board that can rotate about a pivot near its center. A boy and a girl are seated on opposite sides of the pivot. The seesaw is not balanced and the end of the board on the girl's side is resting on the ground. It will balance if
a) the boy moves closer to the pivot.
b) the boy weighed less.
c) the girl moves farther from the pivot.
d) the girl moves closer to the pivot.
e) These two will never be able to make it balance.
17. A home mechanic applies a 75 N force to the handle of a wrench to turn a rusted nut. Which point of application and direction of this force shown in Figure 4 will result in the largest torque.
a) 2 b) 3 c) 1 d) 4 e) 5
18. A stationary van shown in Figure 2 has a wheelbase of 2.2 m, a normal force of 4500 N acting on each of its front wheels, and a normal force of 2500 N acting on each of its rear wheels. The van's center of mass is located _____ m behind the front wheels.
a) 1.41 b) 0.39 c) 1.22 d) 0.79 e) 3.96
_____________________________________________________________________________________
19-20. A 100 kg Santa Claus is suspended by a cable. The middle of the cable is pulled to the right as shown in Figure 3.
19. The tension T1 in the upward slanting cable is __________ N.
a) 1960 b) 19.6 c) 200 d) 1132 e) 1697
20. The tension T2 in the horizontal cable is __________ N.
a) 980 b) 2263 c) 3920 d) 1960 e) 1697
Return to the top of the Exam results home page.