Velocity / Acceleration

Review

Average Velocity

1. A cheetah can run short distances at top speeds of up to  31 meters per second, three times the speed of a human sprinter. How far would a cheetah travel in 3.2 seconds running at top speed?

2. On a clear day, two students take a three-hour automobile trip to enjoy the fall foliage. In the first two hours, they travel 100 km at a constant speed. In the third hour, they travel another 80 km, at a different constant speed. What is the average speed for each segment and for the entire trip?

3. A homing pigeon is released from under the center of the Gateway to the West Arch in St. Louis. (a) What is its average velocity: (i) if it travels 50 km due east from the arch in one hour? (ii) if, instead, it travels 50 km west from the arch in one hour? (iii) if it starts 10 km east of the arch, travels to 20 km east of the arch, and then travels to 30 km west of the arch in one hour? (b) What would the average speed be in each of these cases?

Acceleration

4. A bicyclist starts from rest and increases her velocity at a constant rate until she reaches a speed of 2.0 m/s in 5.0 s. What is her average acceleration?

5. A motorcyclist starts from rest and accelerates in one direction with a constant acceleration of 4.0 m/s/s for 12 s. What is the rider's velocity at the end of the 12 s?

Motion With Constant Acceleration

6. A Boeing 747 airliner, initially at rest, undergoes a constant acceleration of 2.3 m/s/s down the runway for 34 s before it lifts off. How far does it travel down the runway before taking off?

7. You are driving your new sports car at a velocity of 90 km/h, when you suddenly see a dog step into the road 50 m ahead. You hit the brakes hard to get maximum negative acceleration of 7.5 m/s/s (a = - 7.5 m/s/s). How far will you go before stopping? Can you avoid hitting the dog?

8. At the six Flags amusement park near Atlanta, Georgia, Free Fall riders seated four abreast in a padded gondola are taken to the top of a 10-story tower. Then the gondola is dropped 30 m down a vertical track then curves near the bottom, where the gondola slows to a stop. (a) How long does it take to fall from the top to the bottom (30 m).  (b) What maximum speed is reached?

9. A salmon is dropped by a hovering eagle. It hits the ground 2.5 seconds later. How high from the ground was the eagle when it dropped the fish?

10. A water balloon is thrown straight down from the roof of a dormitory at 10.0 m/s. If the building is 100-m tall, (a) at what velocity will the ball hit the ground? (b) How long will the trip take.

11. The eagle above gets another salmon, again it drops the salmon when hovering at 8.0 meters from the ground. (a) How long does it take the salmon to hit the ground?  (b) What is the salmon's velocity when it hits the ground?

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Thanks,

Mr. Clark