vf = vi + at
vf2 = vi2 + 2a∆x
∆x = ½ (vi + vf)t
Unit 7 Review Sheet – Projectiles Only
∆x = vit + ½ at2
Name ___________________________
Date ____________________________
Projectile Concepts
1. Consider these diagrams in answering the following questions.
Which diagram (if any) might represent…
a. …the initial horizontal velocity?
b. ... the initial vertical velocity?
c. ... the net force?
d. ... the horizontal acceleration?
e. ... the vertical acceleration?
2. Supposing a snowmobile is equipped with a flare launcher that is capable of launching a sphere vertically (relative
to the snowmobile). If the snowmobile is in motion and launches the flare and maintains a constant horizontal
velocity after the launch, then where will the flare land (neglect air resistance)?
a. in front of the snowmobile
b. behind the snowmobile
c. in the snowmobile
3. Suppose a rescue airplane drops a relief package while it is moving with a constant horizontal speed at an elevated
height. Assuming that air resistance is negligible, where will the relief package land relative to the plane?
a. below the plane and behind it.
b. directly below the plane
c. below the plane and ahead of it
Questions 4 - 8 refer to the following situation:
A tennis ball is thrown with a velocity of10 m/s 45 ° above horizontal.
Point A is immediately after it leaves the hand.
Point B is the highest point of the trajectory,
Point C is on the same level as A, and
Point D is immediately before it lands.
4. At which of the locations is the velocity of the ball zero m/s?
A) A
B) B
C) C
D) D
E) none of these locations
5. At which of the locations is the ball’s velocity not changing?
A) A
B) B
C) C
D) D
E) the v is always changing
6. How does the velocity of the ball compare at positions A and C?
A) The velocity is exactly the same at A and C.
B) The magnitude of the velocity is the same at A and C, but the direction is not.
C) The ball is going faster at A than at C.
D) The ball is going faster at C than at A.
7. Which statement is true concerning the ball when it is at B?
A) The velocity is zero m/s.
B) The acceleration is zero m/s/s.
C) Both the velocity and the acceleration are zero
D) The velocity is 10 m/s
E) A-D are all false
8. How do the times for the ball to go from A to B, and from B to C compare?
A) tup = tdown
B) tup < tdown
C) tup > tdown
Projectile Problems
9. An emergency relief plane is dropping a care package from a plane to a group of medical personnel working for a
relief agency in an African village. The package is designed to land in a small lake, inflate an attached raft upon
impact, and finally resurface with the raft side down. The plane will be moving horizontally with a ground speed
of 59.1 m/s. The package will be dropped a horizontal distance of 521 m from the intended target location.
a. At what altitude above the pond must the plane be flying in order to successfully accomplish this feat?
b. With what velocity does the package hit the ground?
10. A tennis player stretches out to reach a ball that is just barely above the ground and successfully 'lobs' it over her
opponent's head. The ball is hit with a speed of 18.7 m/s at an angle of 65.1 degrees.
a. Determine the time that the ball is in the air.
b. Determine the maximum height which the ball reaches.
c. Determine the distance the ball travels horizontally before landing.
d. What is the final (impact) velocity of the ball as it lands?
11. Albert is South’s star punter for the varsity football team. His best hang time this past season was for a punt which
he kicked at 74° above the horizontal. The punt had a 6.2 second hang time.
a. Determine the speed at which the ball was punted.
b. Determine the horizontal distance which the ball traveled.