Download Sample exam 2

3650:291-001
Exam 2
sin 30o = cos 60o = 0.5
SD
02/11/05
sin 60o = cos 30o = 0.87
1. “Whenever one object exerts a force on a second object, the second exerts an equal
and opposite force on the first.” This is the definition of which Newton’s law of
motion?
(a) First
(b) Second
(c) Third
(d) Fourth
2. Newton’s second law can be expressed as:
(a)
(b)
(c)
F = mv
F = ma
a = mF
3. A 0.1-kg baseball traveling 10 m/s strikes the catcher’s mitt, which, in brining the ball
to rest, recoils backward 0.5 m. What was the magnitude of the force applied by the ball
on the glove?
(a) 0
(b) 10 N
(c) 100 N
(d) none of these
Questions 4-5. Consider the forces F1 and F2 below:
y
F1= 10 N
60o
30
o
x
F2= 10 N
4. What is the magnitude of the x component of the resulting force F1+F2?
(a) 0
(b) 3.7 N
(c) 8.7 N
(d) 10 N
5. What is the magnitude of the y component of the resulting force F1+F2?
(a) 0
(b) 3.7 N
(c) 8.7 N
1
(d) 10 N
Questions 6-7. Consider two boxes with masses m1=1 kg and m2=2 kg connected by a
cord whose mass can be neglected. Assume there is no friction.
m1
m2
6. The acceleration of the system is:
(a) 0
(b) 1 m/s2
(c) 3.27 m/s2
(d) 9.8 m/s2
(c) 13.07 N
(d) 19.60 N
7. The tension in the cord is:
(a) 0
(b) 9.80 N
Questions 8-9. A 10.0-kg box is pulled along a horizontal frictionless surface by a force
Fp= 20.0 N which is applied at a 30o angle with respect to the horizontal.
8. What is the acceleration of the box?
(a) 0
(b) 1.74 m/s2
(c) 2 m/s2
(d) none of these
9. The magnitude of the normal force on the box is:
(a) 0
(b) 88 N
(c) 98 N
(d) none of these
10. The force of friction is always oriented in the opposite direction from the direction of
motion.
(a) True
(b) False
(c) cannot be answered
2
Questions 11 – 13. Consider the system shown below: two boxes with masses m1=1 kg
and m2=2 kg are connected by a cord running over a pulley. The coefficient of kinetic
friction between box I and the table is 0.20. Neglect the mass of the cord and the pulley,
and any friction in the pulley.
m1
m2
11. What is the acceleration of the system?
(a) 0
(b) 0.6 g
(c) 1.5 g
(d) 3 g
(c) 9.8 N
(d) 19.6 N
(c) 9.8 N
(d) 19.6 N
12. What is the normal force on box m1?
(a) 0
(b) 1 N
13. What is the normal force on box m2?
(a) 0
(b) 1 N
Questions 14-15. Consider a box of mass m moving along an incline with angle θ.
Coefficient of kinetic frictions is µ k.
14. The acceleration of the box is:
(a) g sinθ
(b) g(sinθ-µ kcosθ)
(c) g cosθ
(d) g(cosθ-µ ksinθ)
15. The magnitude of friction force is:
(a) µ k m g cosθ
(b) µ k m g sinθ
3
(c) mg(sinθ-µ kcosθ)
Questions 16 – 17. A box of mass m1=10 kg rest on a surface inclined at θ= 30o to the
horizontal. It is connected by a lightweight cord, which passes over a massless and
frictionless pulley, to a second box of mass m2=10 kg, which hangs freely, as shown
below. The coefficient of kinetic friction is µ k=0.1. Take g 10 m/s2.
m1
m2
θ=30ο
16. What is the acceleration of the system?
(a) 0
(b) 1.03 m/s2
(c) 2.07 m/s2
(d) 4.13 m/s2
(c) 98 N
(d) 100 N
17. What is the normal force on box m1?
(a) 0
(b) 87 N
18. The net force on an object executing uniform circular motion is always oriented away
from the center of the circle.
(a) True
(b) False
(c) cannot be answered
Questions 19-20. A 0.1-kg ball on the end of a 1-m long cord (whose mass is negligible)
is swung in a horizontal circle. The ball makes 1 revolution per second.
19. What is the centripetal acceleration of the ball?
(a) 0
(b) 3.14 m/s2
(c) 6.28 m/s2
(d) 39.4 m/s2
20. What is the magnitude of the net radial force on the ball?
(a) 0
(b) 3.14 N
(c) 3.94 N
4
(d) 6.28 N