Assignment 3 Prelims

Assignment 2 Prelims

Constant Acceleration

1. An electric vehicle starts from rest and accelerates at a rate of 2.0 m/s2 in a straight line until it reaches a speed of 20 m/s. The vehicle then slows at a constant rate of 1.0 m/s2 until it stops.
(a) How much time elapses from start to stop?
(b) How far does the vehicle travel from start to stop?

2. A world's land speed record was set by Colonel John P. Stapp when in March 1954 he rode a rocket-propelled sled that moved along a track at 1020 km/h. He and the sled were brought to a stop in 1.4 s. In terms of g, what acceleration did he experience while stopping? 1 g = 9.8 m/s2.

Free-Fall Acceleration

3. Raindrops fall 1800 m from a cloud to the ground.
(a) If they were not slowed by air resistance, how fast would the drops be moving when they struck the ground?
(b) Would it be safe to walk outside during a rainstorm?

4. At a construction site a pipe wrench struck the ground with a speed of 24 m/s.
(a) From what height was it inadvertently dropped?
(b) How long was it falling?

Assignment 1 Prelims

Answer the following problems:

1. During a hard sneeze, your eyes might shut for  0.50 s.  If you are driving a car at 90 km/h during such a sneeze, how far does the car move during that time?

2. A car travels up a slope at a constant speed of 45 km/h for 20.0 min and returns down the slope to its place of origin at a constant speed of 65 km/h. What is the average speed for the total trip?

3. Two trains, each having a speed of 30 km/h, are headed at each other on the same straight track. A bird that can fly 60 km/h flies off the front of one train when they are 60 km apart and heads directly for the other train. On reaching the other train, the bird flies directly back to the first train. What is the total time and distance the bird travels for this entire flying trip?

Note: These problems are adapted from PRINCIPLES of PHYSICS, 9th Edition, International Student Version by Jearl Walker. John Wiley & Sons, Inc. Copyright 2011.