1. A rocketship coasting at 20,000 m/s in deep
space fires its engines so that it accelerates at 20 m/s/s.
a) How long will it have to keep accelerating to
get to a speed of 300,000 m/s?
b) How far will it travel while it is
accelerating?
2. The head of a rattlesnake can accelerate at
50 m/s/s when it strikes. The
rattlesnake’s head starts from rest and accelerates constantly until it strikes
a victim that is 0.5 m away.
a) How fast is the snake’s head moving when it
hits the victim?
b) How long does it take the snake’s head to get
to the victim?
3. A world land speed record was set by Colonel
John P. Stapp on March 19, 1954 when he rode a rocket-propelled sled at 283.3
m/s. The sled (and the colonel) was
brought to a stop in 1.4s. What
acceleration did the colonel experience?
4. Ben is inspired by Colonel Stapp’s example to
take up rocket sledding. He builds a
track so he can get a modern rocket sled to go from rest up to 445 m/s.
a) If his track is only 225 m long, how quickly
will Ben (and the rocket sled) have to accelerate to reach the target speed by
the end of the track?
b) How much time will it take the sled to go
from one end of the track to the other?
5. A high-speed train starts from rest and moves
with constant acceleration. As it passes
a speed trap, a bored police officer uses a radar gun to measure the train’s
speed as 30 m/s. At another speed trap,
160 m further down the track, another officer measures the train’s speed as 50
m/s.
a) How quickly was the train accelerating?
b) How long did it take to travel the 160 m
between speed traps?
6. Cole is driving his car at 25.6 m/s along a
dark road. As he approaches a bridge, he
notices several “Bridge Out” signs and hits the brakes. Two seconds later, the car tumbles over the
edge of the missing bridge, 34 m from where he noticed the signs.
a) How fast was the car going when it tumbled
off the bridge?
b) How quickly was the car accelerating while it
braked?
7. A subway train accelerates gradually (a = 1.2
m/s/s) from rest at one station until it is halfway to the next station and
then decelerates gradually (a = -1.2 m/s/s) for the final half of the trip
until it comes to rest. The two stations
are 1100 m apart.
a) What is the maximum speed the train reaches?
b) How long does it take to travel between the
stations?
8. Heather is sitting in her car at a
stoplight. At the instant the light
turns green, she starts accelerating at 2.2 m/s/s. At the same moment a truck rumbles past her
car going a constant speed of 12.2 m/s.
Heather is infuriated at being passed by a truck and she keeps
accelerating until she gets ahead of the truck.
a) How much time will it take her to catch up
with the truck?
b) How far down the street will she catch up
with the truck?
c) How fast will she be moving at this point?
