MYIB / Honors Physics
Mid Term Exam Review
1.
Explain the difference between speed and velocity.
2.
Acceleration is the rate at which ______.
3.
What is the rate of acceleration of an object experiencing free fall?
4.
For an object thrown upward, a.
What is its speed at its highest point? b.
What is its acceleration at its highest point?
5.
A car starts from rest and reaches a speed of 50 m/s over a 8.0 s period. What is the car’s acceleration?
6.
A weather balloon is floating at a constant height above the ground when it releases a pack of instruments. a.
If the pack hits the ground at a speed of 78.5 m/s, what is the height of the balloon? b.
How long does it take the pack to fall from the balloon to the ground?
7.
A car comes to a stop after a uniform deceleration of 7.0 m/s 2 for 6 s. What distance is traveled by the car during this time?
Use the following Position vs. Time graph for questions 8 – 10.
8.
When is the object going the fastest?
9.
What times are the object is moving at the same speed?
10.
What is the instantaneous velocity at t = 15 s?
Use the following velocity vs. time graph for questions 11 – 13.
11.
When was the object moving with constant speed?
12.
What was the acceleration of the object during the first 2 s?
13.
What was the displacement for the entire trip?
14.
A plane travels a distance of 500 km in a direction 30 o North of East. a.
What is the North component of the plane’s motion? b.
What is the East component of the plane’s motion?
15.
A hiker leaves camp and walks 14 km due North and 20 km due West.

a.
What is the distance walked by the hiker? b.
What is the displacement of the hiker from the starting point?
16.
A tiger leaps horizontally from a 17 meter high rock with a speed of 3.5 m/s. How far from the base of the cliff will she land?
17.
A steel ball rolls with constant velocity across a level tabletop. The tabletop is 0.675 m in height. It rolls and hits the ground 0.276 m from the edge of the table. How fast was the ball rolling?
18.
A player kicks a football from ground level with an initial velocity of 32.0 m/s, 38  above the horizontal.
Find the ball’s hang time, range, and maximum height.
19.
A 3670 kg helicopter accelerates upward at 4.0 m/s 2 . What lift force is exerted by the air on the propellers?
20.
A crane holds a wrecking ball that weighs 108,000 N. a.
What upward force does the crane exert on the wrecking ball? b.
If the crane begins to move the wrecking ball upward with an acceleration of 4.2 m/s 2 , what force is the crane exerting on the wrecking ball?
21.
A sled of mass 75.0 kg is pulled along snow covered flat ground. The coefficient of sliding friction is
0.35. What force is needed to keep the sled moving at a constant velocity?
22.
A 16.0 N force is applied at 24.0
 above the horizontal to a 1.5 kg brick to drag it across a table. The coefficient of sliding (kinetic) friction is 0.43. a.
What is the normal force acting on the brick? b.
What is the force of friction acting on the brick? c.
What is the acceleration of the brick?
F a
= 16.0 N
1.5 kg
23.
Define inertia.
24.
If the box resting on the surface below has a mass of 5 kg and a frictional force of 20 N, draw and label a free body diagram with forces that would cause the box to remain at rest.
25.
A boat heads directly across a river 50 m wide that has a current flowing at 5.2 m/s. The boat can travel at a speed of 6.5 m/s in still water. a.
If the boat tries to go straight across the river, what will be its resultant velocity with respect to the shoreline? b.
How long does it take the boat to cross the river? c.
How far downstream (in relation to the starting point) is the boat after is crosses the river?
26.
(III) The following forces act concurrently on point P.
A: 15 N @ 0 o
B: 25 N @ 110 o
C: 5 N @ 180 o
D: 65 N @ 270 o a.
What is the magnitude and direction of the resultant? b.
What is the magnitude and direction of the equilibrant?
27.
If a projectile was launched at point A at an angle of 30˚ a velocity of 25 m/s, determine the velocities at points A, and C. and
B,

28. What is the relationship between acceleration and velocity?
29. (II) A young boy swings a 0.30 kg yo-yo horizontally above his head. The string is 75 cm long and it takes 0.5 s for the yo-yo to make one revolution. a) What is the angular speed (frequency) of the yo-yo? b) What is the linear speed of the yo-yo? c) What is the centripetal acceleration of the yo-yo? d) What is the tension in the string?
30. (III) A test pilot volunteers to test the limits of a new high-performance fighter plane. The engineers say the jet is capable of flying in a horizontal circle at a speed of 99 m/s. The 75.0 kg pilot does not want his centripetal acceleration to exceed 7 g's (7 times free fall acceleration). What is the minimum radius of the circular path for the plane?
31. What is centripetal force?
32. What is a net force?
33. What is the difference between static friction and kinetic friction? Which coefficient of friction is larger: static or kinetic?
34. (I) Two bowling balls each have a mass of 6.5 kg. The spheres are located next to one another with their centers 31.5 cm apart. What gravitational force do they exert on each other?
35. What is gravitational force?
36. What is the mass of the toy truck if the force of friction holding it in place is 28.5 N?
37.
(II) A 425 kg block accelerates across the floor as the result of an applied force of 1600 N to the right. The sliding frictional force is 800N.
800 N
425 kg
1600 N
30
 a.
What is the net force causing the acceleration? b.
What is the magnitude and direction of the acceleration? c.
What is the coefficient of friction between the block and the floor?
38. Using F=ma, answer the following questions about the relationships between force, mass and acceleration: a. if the mass of the object is doubled, what happens to the force? b. if force remains the same, and the mass is doubled, what happens to the acceleration?
39. Using the F g equation, explain the relationships between force, mass and distance: a. if the gravitational force doubles, what has happened to the distance? b. if the mass of one of two objects doubles, what happens to the gravitational force?

Answers
1.
Velocity has a direction
2.
velocity changes
3.
-9.8 m/s 2
4.
a) 0 m/s b) -9.8 m/s 2
5.
6.25 m/s 2
6.
a. 314 m b. 8.01 s
7.
126 m
8.
t = 0s – 5s
9.
t = 10s – 20s and t = 25s – 30s
10.
– 2.00 m/s
11.
t = 2s – 8s t = 16s – 18s
12.
1m/s 2
13.
8m
14.
a) 250 km b) 433 km
15.
a) 34 km b) 24.4 km @ 35 o North of West
16.
6.51 m
17.
0.744 m/s
18.
4.02 s; 101 m; 19.8 m
19.
50,600 N
20.
(a) 108,000 N (b) 154,000 N
21.
257 N
22.
(a) 8.2 N (b) 3.53 N (c) 7.38 m/s 2
23.
The tendency of an object to resist a change in its motion
24.
4 forces: F
N
up and mg down (each 49 N), F
A
and F f
horizontal toward opposite sides of the page(each 20 N)
25.
a) 8.32 m/s, 51.3° w.r.t. shoreline b) 7.69 s c) 40 m
26.
a) 41.53 N @ 272° b) 41.53 N @ 92°
27.
A: 25 m/s, 30° above horizontal (v x
= 21.7 m/s, v y
= 12.5 m/s)
B: 21.7 m/s to the right (v x
= 21.7 m/s, v y
= 0 m/s)
C: 25 m/s, 30° below horizontal (v x
= 21.7 m/s, v y
= –12.5 m/s)
28.
Acceleration is the change in velocity per unit time; it is the slope of the velocity-time graph.
29.
(a) 2.0 rev/s (b) 9.42 m/s (c) 118 m/s 2 (d) 35.5 N
30.
143 m
31.
The force required to keep an object moving in a circle; it is always provided by a net force pointing toward the center of curvature of the object’s motion; it is not a separate force on the free body diagram
32.
The (vector) resultant of all the forces acting on an object
33.
Static friction is between objects at rest relative to each other; kinetic friction is between objects in motion relative to each other (i.e. surfaces sliding against each other); coefficient of static friction is larger
34.
2.84 × 10 –8 N
35.
The force of attraction between any two massive objects (a.k.a. weight in the context of one object being attracted to a planet or planetoid)
36.
5.82 kg
37.
(a) 800 N (b) 1.88 m/s 2 to the right (c) 0.192
38.
(a) force doubles (b) acceleration is halved
39.
(a) distance has decreased: multiplied by a factor of 1/√2 (b) force doubles