Forces and Motion

A cyclist increases her speed from to in seconds. Calculate her acceleration.

Which of the following describes velocity but not speed?

State the difference between speed and velocity.

The distance-time data for a moving object is shown below.

A car travels at a constant speed of 20 m/s north and then turns to travel 20 m/s east. Explain how its speed and velocity change.

A runner accelerates from rest to a speed of 6 m/s in 3 s.

A car slows down from 18 m/s to 6 m/s in 4 seconds. Calculate its acceleration.

Explain why velocity is a vector quantity but speed is a scalar quantity.

A boat travels at a constant speed of 5 m/s across a river that is 100 m wide. The current flows east at 3 m/s, and the boat points directly north (perpendicular to the current).

Explain the difference between the speed of the boat and its velocity as it crosses the river. Give your answer in terms of scalar and vector quantities, and describe the actual path of the boat across the river.

A cyclist travels in a straight line and accelerates from an initial velocity of to a final velocity of in 3.0 seconds. Calculate the cyclist’s acceleration. Explain what the negative and positive signs of velocity indicate, and describe what happens to the cyclist’s motion over this time.