g=10 m/s 2, sin 37

University of Bahrain Physics 101 Test 2 Fall 2003
Physics Department Tuesday, 30/12/2003 60 minutes
Name:
Instructor Name:
ID no.:
Section:
Use: g=10 m/s 2 , sin 37 ◦ = cos 53 ◦ = 0.6, sin 53 ◦ = cos 37 ◦ = 0.8
Choose the correct answer for the following questions:
1. An 80 kg athlete starts running from rest to a speed of 5 m/s. The net work done (in J)
is:
(a) 1000 (b) 1440 (c) 1960 (d) 2560
2. A force of 10 N stretches a spring 5 cm from its equilibrium point. The work (in J) needed
to stretch the spring 30 cm is:
(a) 4 (b) 9 (c) 16 (d) 25
3. A block is pushed for 2 m on a rough surface by a force
F =20 N. If the block moves with a constant speed, then
the work done (in J) by friction is:
(a) -20 (b) -40 (c) -60 (d) -80
F
2 m
4. A 2 kg block is pulled 2 m up a 37 ◦ smooth incline by a force
F , as in the figure. If the total work done is 30 J, then the
magnitude of the force F (in N) is:
(a) 27 (b) 32 (c) 37 (d) 42
2 m
F
37 o
5. A 1 kg block slides from rest down the smooth track from
a height of 2 m, and comes to rest after compressing a
spring a distance x=10 cm. The force constant k (in N/m)
of the spring is:
1 kg
2 m k
(a) 160 (b) 250 (c) 1000 (d) 4000

6. A block leaves a 53 ◦ incline with a speed of v=15 m/s, point
A. The maximum height h max (in m) reached by the block
above A is:
(a) 0.8 (b) 3.2 (c) 7.2 (d) 12.8
v
A
53 o
h max
7. A block slides down a smooth curved track and then up
a rough 37 ◦ incline with µ k =0.2, as in the figure. If the
block slides down from rest from a height h 0 =1.5 m,
then the maximum height h max (in m) reached by the
block on the rough incline is:
h o
37 o
h max
(a) 0.39 (b) 0.79 (c) 1.18 (d) 1.58
8. A 100 kg roller coaster car rolls from rest at point A. If
the car speed at point B is 11 m/s, then the work (in
J) done by friction is:
(a) -1550 (b) -2800 (c) -3950 (d) -5000
30 m
A
B
r=10 m
9. A 10 g bullet is fired with a speed v=240 m/s at a resting
2 kg wood block. If the bullet exits the block at half its
original speed, then the block speed V (in m/s) after the
collision is:
v V v / 2
(a) 0.3 (b) 0.4 (c) 0.5 (d) 0.6
10. A 1500 kg car moving with a speed v i =15 m/s, collides with a wall
and rebounds with a speed v f =3 m/s. If the collision lasts 0.2 s,
then the magnitude of average force (in N) exerted on the car by
the wall is:
(a) 54000 (b) 67500 (c) 90000 (d) 135000
v i
v f
11. Two identical balls each with a speed of 20 m/s collided, as
shown in the figure. After the collision, one of the ball had a
speed v ′ 1=10 m/s in the shown direction. The speed v ′ 2 (in m/s)
of the other ball is:
(a) 18.4 (b) 20.4 (c) 22.4 (d) 24.3
v 1
20 m/s
v 2
20 m/s
v’ 1 =10 m/s
37 o
v’ = 2 ?
12. A block with mass 2m moving with a speed v collides
with and stick to a stationary block of mass m. After
the collision the two blocks move a maximum vertical
height h max =0.4 m up the smooth track. The initial
speed of the block, v, in m/s is:
m 2 v
m
h max
(a) 3.0 (b) 4.2 (c) 5.2 (d) 6.0