Homework 6
Show all work with units for short answer problems.
1. In a drill during basketball practice, a player runs the length of the 30.-meter court and back.
The player does this three times in 60. seconds.
The average speed of the player during the drill is
2. A group of bike riders took a 4.0-hour trip. During the first 3.0 hours, they traveled a total of 50.
kilometers, but during the last hour they traveled only 10. kilometers. What was the group's average
speed for the entire trip?
3. A car accelerates uniformly from rest at 3.2 m/s2. When the car has traveled a distance of 40. meters,
its speed will be
4. What is the final speed of an object that starts from rest and accelerates uniformly at 4.0 meters per
second 2 over a distance of 8.0 meters?
5. A truck, initially traveling at a speed of 22 meters per second, increases speed at a constant rate of 2.4
meters per second 2 for 3.2 seconds. What is the total distance traveled by the truck during this
3.2-second time interval?
Homework 6
6. The graph below represents the relationship between velocity and time for an object moving along a
straight line.
What is the magnitude of the object's acceleration?
7. The graph below shows the relationship between the speed and elapsed time for an object falling freely
from rest near the surface of a planet.
What is the total distance the object falls during the first 3.0 seconds?
8. A rocket initially at rest on the ground lifts off vertically with a constant acceleration of 2.0 × 101
meters per second 2. How long will it take the rocket to reach an altitude of 9.0 × 10 3 meters?
9. Oil drips at 0.4-second intervals from a car that has an oil leak. Which pattern best represents the
spacing of oil drops as the car accelerates uniformly from rest?
A) B)
C) D)
Homework 6
10.A roller coaster, traveling with an initial speed of 15 meters per second, decelerates uniformly at –7.0
meters per second 2 to a full stop. Approximately how far does the roller coaster travel during its
deceleration?
11. An observer recorded the data above for the motion of a car undergoing constant acceleration.
What was the magnitude of the acceleration of the car?
12. Which pair of graphs represents the vertical motion of an object falling freely from rest?
A) B)
C) D)
13. Which pair of graphs represents the same motion of an object?
A) B)
C) D)
Homework 6
14. Which graph represents the motion of an object traveling with a positive velocity and a negative
acceleration?
A) B)
C) D)
15. The displacement-time graph below represents the motion of a cart initially moving forward along a
straight line.
During which interval is the cart moving forward at constant speed?
A) AB B) BC C) CD D) DE
Homework 6
Base your answers to questions 16 through 18 on the information below.
A car on a straight road starts from rest and accelerates at 1.0 meter per second2 for 10. seconds. Then
the car continues to travel at constant speed for an additional 20. seconds.
16. Determine the speed of the car at the end of the first 10. seconds.
17. On the grid provided, use a ruler or straightedge to construct a graph of the car's speed as a function
of time for the entire 30.-second interval.
18. Calculate the distance the car travels in the first 10. seconds. [Show all work, including the equation
and substitution with units.]
Homework 6
19. Two physics students have been selected by NASA to accompany astronauts on a future mission to
the Moon. The students are to design and carryout a simple experiment to measure the acceleration
due to gravity on the surface of the Moon.
Describe an experiment that the students could conduct to measure the acceleration due to gravity on
the Moon. Your description must include:
• the equipment needed
• what quantities would be measured using the equipment
• what procedure the students should follow inconducting their experiment
• what equations and/or calculations the students would need to do to arrive at a value for the
acceleration due to gravity on the Moon
20. Base your answer to the following question on the information and diagram below.
A child is flying a kite, K. A student at point B, located 100. meters away from point A (directly
underneath the kite), measures the angle of elevation of the kite from the ground as 30.0°. (Image of
kite diagram not to scale)
A small lead sphere is dropped from the kite. Calculate the amount of time required for the sphere to
fall to the ground. [Show all calculations, including the equation and substitution with units. Neglect
air resistance.]
