Unit 3 Motion

Show all formulae used, and all calculations to arrive at final answers.

Diagrams are useful for accurate set-up of problems. They are required in some questions.

Final answers must include units, and the correct number of significant digits. Please circle final answers.

1. A giraffe can accelerate from rest to a speed of 18.5 m/s in 9.45s. What is its average acceleration?

2.A truck driver moves out of his parking spot, into traffic, at a constant acceleration of 1.04 m/s². Assume that the initial motion is in the positive direction.

A)How long does it take the driver to reach a speed of 3.75 m/s?

B) The driver is then cruising at a speed of 3.75m/s and sees a red light ahead.He slows to a stop, over a period of 0.950s. What was his acceleration during this time period?

3. A bullet in a gun is accelerated from rest from the firing chamber to the end of the barrel at an average rate of 5.44 x 10⁵ m/s² for 1.35x 10^-4s. What is the gun's muzzle velocity? (This is the bullet's speed as it leaves the muzzle).

4. During a hockey game, a player makes a shot which they accelerate the puck from a velocity of 6.50 m/s to 31.0 m/s in one direction. The shot takes 6.05 x 10^-2s. Calculate the distance, in metres, over which the puck accelerated.

5. A train engine, pulling a multi-car load of rock, produces small accelerations and decelerations.

A) What is the final velocity, in metres per second, of a train that accelerates at a rate of 0.0430 m/s² for 3.05 minutes, starting with an initial velocity of 4.15 m/s?

B) If the train can slow down at a rate of 0.410m/s², how long, in seconds, does it take to come to a stop from the velocity it reached in part a)?

6. A Coast Guard Helicopter is hovering over a sinking sailboat to rescue one of the crew members aboard. One of the rescuers throws a life ring straight down to the person with an initial speed of 1.15m/s and sees that it takes 2.25s to reach the water. How high above the water was the life ring released? (**The downdraft of the helicopter reduces the effect of air resistance on the falling life ring, so that an acceleration equal to gravity is reasonable).

7. A ball is kicked at ground level with an initial velocity of 19.5 m/s in the horizontal, and 12.7 m/s in the vertical.

** Diagram required.

A)At what speed does the ball hit the ground? (m/s)

B)For how long does the ball remain in the air? (s)

C) What maximum height does the ball reach? (m)

8. Near the end of a 10k footrace, the first two runners are separated by 50.5 m.The front runner has a velocity of 3.05 m/s and the second, a velocity of 4.33 m/s.

A) What is the velocity of the second runner, relative to the first, in metres per second?

B) How many seconds earlier will the second runner reach the finish line, if the front runner is 208m from the finish line?

C)What distance ahead of the other runner, in metres, will the second runner be when she crosses the finish line?

9.A container ship sets out from Sydney, Nova Scotia, intending to head due north at 3.40 m/s relative to the water. However, the local ocean current is moving at 1.85m/s in a direction 36.0 north of east, and it changes the ship's intended motion.

*Diagram required.

A) In what direction would the ship have to travel in order to have a resultant velocity straight north relative to the earth, assuming the speed relative to the water remains 3.40 m/s? Give the angle in degrees.

B) What would the ship's speed be, relative to the earth, in metres per second?

10. A team of junior Olympic sailors have set their Laser sailboat on a course of 60.5 west of north, at 4.77m/s. They encounter a current, which is traveling from 31.5 south of west, at 1.90m/s. What is the resultant velocity of the sailboat?

*Diagram required.