Math 1210-007
Practice Problems
Fall 2010
Practice Problems - 11/8/10
Reminder: You can use Google to convert many of these units. For example, type "convert 10
meters to feet" into the Google search box and watch what happens!!
1.
NASCAR!!
(Remember to convert all of your units appropriately)
(a)
A race car is said to go "zero to sixty in 3.1 seconds" (60 mph), assuming the
driver puts the petal to the metal. What is its acceleration in meters per second squared?
Answer = 5.899 m/s2
(b)
Suppose the driver can't release his foot from the gas pedal which causes the car
to continue accelerating at the same rate. How many additional seconds would it take for
the driver to reach 80 mph?
Answer = 1.0333 s
(c)
When the driver reaches exactly 80mph he then slams on the breaks. What rate of
deceleration would be required by the breaks in order to make the car stop completely in
exactly 5 seconds? Express your answer in units of meters per second squared.
Answer = -4.877 m/s2
2.
A baseball is pitched at 40 m/s (90 mph) in a Major League game. The batter hits the ball
on a line drive straight toward the pitcher at 50 m/s (112 mph). Determine the acceleration of the
ball if it was in contact with the bat for 1/30 seconds.
Answer = 2,700 m/s2
3.
A rocket can launch a space shuttle away from the surface of the earth with an
acceleration of 20 feet per second squared and an initial speed of 0 feet per second.
(a)
How long will it take the shuttle to reach the height of Mt. Everest (29,028 ft.)?
Answer = 53.878 s
(b)
After 3 minutes the rockets are released from the shuttle. Assuming the shuttle
was moving exactly vertically the entire time, what is the shuttle's velocity at the time the
rockets are released?
Answer = 3,600 ft/s
(c)
How high off the ground is the shuttle at the moment the rockets are released?
Answer = 324,000 ft
(d)
If the shuttle were allowed to continue moving freely it would eventually fall back
onto the earth. How long would this take (make the simplifying assumption that earth's
gravity continues to cause the shuttle to accelerate downward at 32 feet per second, in
reality the gravitational pull of the earth is weaker at higher altitudes).
Answer = 293.9 s