Download According to Newton`s ______ law, an object with no net force

FINAL EXAM REVIEW KEY
PHYSICS
FIRST SEMESTER (01/2012)
UNIT 1 — Motion
1.
29.2 cm/s = 0.292 m/s
2. 45 mi/h
3.
a.
b.
c.
d.
C
A
B
C
4. (P2.1C) Make a position time graph for each object
in the table above.
Position (m)
Object A
5
5
5
5
5
5
9
Position (m)
Object B
0
1
3
5
7
9
8
7
Position (m)
Time
(s)
0
1
2
3
4
5
10
6
5
Object A
4
Object B
3
2
1
5.
a.
b.
c.
d.
2 m/s
4 m/s
0 m/s
6 m/s
0
0
1
2
3
4
5
Time (s)
6. 6.2 s
7. 420 miles
8. 0.64 s
9. (P2.2A) Which of the following are vectors? Which of the following are scalars?
a. Distance scalar
e. Velocity vector
b. Time scalar
f. Acceleration vector
c. Displacement vector
g. Mass scalar
d. Speed scalar
11. 27 s
12. 26 m/s
13. -29.4 m/s
14.
20
15
10
5
Velocity
10. a. distance = 200 yards; displacement = 0 yards
b. speed = 8.33 yards/sec; velocity = 0 yards/sec
0
-5 0.0 1.0 2.0 3.0 4.0
-10
15.
a. 60 m
b. 10 m/s2
-15
-20
Time
UNIT 2 — Two-Dimensional Motion and Forces
16.
a. Horizontal velocity (vx) is constant and is equal to the initial velocity in the x-direction. Vertical velocity (vy) will
decrease (becoming more negative) throughout its fall.
b. The direction of acceleration is straight down and equal to -9.8 m/s2.
17. The ball will fall back into the person's hand.
18.
a. 444 N ┴ to the ramp
b. 0 N
19.
a. 381.9 N ┴ to the ramp
b. 220.5 N down the ramp
20.
17.5 m
21.
0.639 s
22. Plane will be directly above the projectile
UNIT 3 — Dynamics
23. Contact forces: normal force, friction force, push, pull, string force, spring force
Field forces: gravitational force, magnetic force, electric force
24. Normal force is the force exerted upon an object by the surface it sits upon. The normal force is ┴ to the surface.
25. 98. N
26.
a.
OR
b.
c.
27. remains the same; 9.8 m/s2
28. backward direction
29. 429.5 N
30. Depending upon the angle, the resultant force could be between 3 N (the resultant force if angle is 180) and 17 N
(the resultant force if angle is 0). If the angle is 90, the resultant force is 12.2 N.
31. For every force acting upon an object, there is an equal and opposite force acting upon a different object.
32.
a. Force of book pushing down on table -- force of table pushing up on book (FN)
b. Force of you pushing door open -- force of door pushing back at you
c. Force of small car hitting large car -- force of large care hitting small car
33. An object at rest will stay at rest unless acted upon by an unbalanced force. An object in motion will stay in constantvelocity, straight line motion unless acted upon by an unbalanced force.
34. unbalanced force
35. to the right
36.
a. 588 N
b. 588 N
c. 498 N
d. 678 N
37.
c. Since the scale is accelerating downward, the net force is directed downward. This means the FN (the force
the scale shows) is less than the Fg.
d. Since the scale is accelerating upward, the net force is directed upward. This means the FN (the force the
scale shows) is greater than the Fg
38. The sum of all the forces acting upon an object (F net) is equal to the mass of that object times its acceleration.
39. 10 N
40. 0.60 m/s2 upward
41. The mass (quantity of matter) does not change regardless of where the object is located. Weight is a function of the
acceleration due to the planet's gravity, so the weight of an object will be different on different planets.
42. mass does not change
43. 245 N
UNIT 4 – Momentum
44. The smaller car will experience a greater change in velocity. The car exerts the same amount of force on the truck as
the truck exerts on the car (equal and opposite). Since the car has a smaller mass, it will experience a greater
acceleration (v/t).
45. In a collision, the acceleration experienced by a large car is smaller than that experienced by a small car since F=ma
and a large car has more mass.
46. 27.2 m/s
47.
a. force would decrease
b. force would increase
48. An air bag increases the "stopping time" of the passenger, decreasing the acceleration experienced by him/her.
49. 6.67 m/s
50. 8.0 m/s to right
51. 12 m/s
52. 2.67 m/s