Questions from Modern Physics

Q: In the fastest measured tennis serve, the ball left the racquet

In the fastest measured tennis serve, the ball left the racquet at 73.14 m/s. A served tennis ball is typically in contact with the racquet for 30.0 ms and starts from rest. Assume constant accelerati...

Q: The human body can survive an acceleration trauma incident (sudden stop

The human body can survive an acceleration trauma incident (sudden stop) if the magnitude of the acceleration is less than 250 m/s2. If you are in an automobile accident with an initial speed of 105 k...

Q: A pilot who accelerates at more than 4g begins to “gray

A pilot who accelerates at more than 4g begins to “gray out” but doesn’t completely lose consciousness. (a) Assuming constant acceleration, what is the shortest time that a jet pilot starting from res...

Q: Can an object with constant acceleration reverse its direction of travel?

Can an object with constant acceleration reverse its direction of travel? Can it reverse its direction twice? In both cases, explain your reasoning.

Q: During an auto accident, the vehicle’s air bags deploy and slow

During an auto accident, the vehicle’s air bags deploy and slow down the passengers more gently than if they had hit the windshield or steering wheel. According to safety standards, air bags produce a...

Q: Falls resulting in hip fractures are a major cause of injury and

Falls resulting in hip fractures are a major cause of injury and even death to the elderly. Typically, the hip’s speed at impact is about 2.0 m/s. If this can be reduced to 1.3 m/s or less, the hip wi...

Q: It has been suggested, and not facetiously, that life might

It has been suggested, and not facetiously, that life might have originated on Mars and been carried to the earth when a meteor hit Mars and blasted pieces of rock (perhaps containing primitive life)...

Q: A car sits on an entrance ramp to a freeway, waiting

A car sits on an entrance ramp to a freeway, waiting for a break in the traffic. Then the driver accelerates with constant acceleration along the ramp and onto the freeway. The car starts from rest, m...

Q: You normally drive on the freeway between San Diego and Los Angeles

You normally drive on the freeway between San Diego and Los Angeles at an average speed of 105 km/h 165 mi/h2, and the trip takes 1 h and 50 min. On a Friday afternoon, however, heavy traffic slows yo...

Q: The graph in Fig. E2.31 shows the velocity of

The graph in Fig. E2.31 shows the velocity of a motorcycle police officer plotted as a function of time. (a) Find the instantaneous acceleration at t = 3 s, t = 7 s, and t = 11 s. (b) How far does the...