PHYSICSFINAL EXAM REVIEW KEYFIRST SEMESTER (01/2012)

UNIT 1 —Motion

  1. 29.2 cm/s = 0.292 m/s
  1. 45 mi/h
  1. a. C

b. A

c. B

d. C

  1. (P2.1C) Make a position time graph for each object in the table above.

Time
(s) / Position (m)
Object A / Position (m)
Object B
0 / 5 / 0
1 / 5 / 1
2 / 5 / 3
3 / 5 / 5
4 / 5 / 7
5 / 5 / 9
  1. a. 2 m/s

b. 4 m/s

c. 0 m/s

d. 6 m/s

  1. 6.2 s
  1. 420 miles
  1. 0.64 s
  1. (P2.2A) Which of the following are vectors? Which of the following are scalars?
  2. Distance scalare. Velocity vector
  3. Time scalarf. Acceleration vector
  4. Displacement vectorg. Mass scalar
  5. Speed scalar

  1. a. distance = 200 yards; displacement = 0 yards

b. speed = 8.33 yards/sec; velocity = 0 yards/sec

  1. 27 s
  1. 26 m/s
  1. -29.4 m/s

15. a. 60 m

b. 10 m/s2

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.

  1. The ball will fall back into the person's hand.
  1. a. 444 N ┴ to the ramp

b. 0 N

  1. a. 381.9 N ┴ to the ramp

b. 220.5 N down the ramp

  1. 17.5 m
  1. 0.639 s
  1. Plane will be directly above the projectile

UNIT 3 — Dynamics

  1. Contact forces: normal force, friction force, push, pull, string force, spring force

Field forces: gravitational force, magnetic force, electric force

  1. Normal force is the force exerted upon an object by the surface it sits upon. The normal force is ┴ to the surface.
  1. 98. N
  1. a. OR b.

c.

  1. remains the same; 9.8 m/s2
  1. backward direction
  1. 429.5 N
  1. 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.
  1. For every force acting upon an object, there is an equal and opposite force acting upon a different object.
  1. 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

  1. An object at rest will stay at rest unless acted upon by an unbalanced force. An object in motion will stay in constant-velocity, straight line motion unless acted upon by an unbalanced force.
  1. unbalanced force
  1. to the right
  1. a. 588 Nb. 588 Nc. 498 Nd. 678 N
  1. c. Since the scale is accelerating downward, thenet 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

  1. The sum of all the forces acting upon an object (Fnet) is equal to the mass of that object times its acceleration.
  1. 10 N
  1. 0.60 m/s2 upward
  1. 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.
  1. mass does not change
  1. 245 N

UNIT 4 – Momentum

  1. 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).
  1. 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.
  1. 27.2 m/s
  1. a. force would decrease

b. force would increase

  1. An air bag increases the "stopping time" of the passenger, decreasing the acceleration experienced by him/her.
  1. 6.67 m/s
  1. 8.0 m/s to right
  1. 12 m/s
  1. 2.67 m/s