Pupil sheet · Acceleration, falling and drag
Acceleration, falling and drag — return questions
Name ______________________ Date ____________
Use one to two weeks after the lessons. Keep the notes and the lesson closed.
1. state / calculate / describe
Keep the lesson closed. (a) State what is meant by acceleration, and give its unit. (b) A runner's speed–time graph is a straight line from 3.0 m/s at 0 s to 7.0 m/s at 2.0 s. Use its gradient to calculate her acceleration. (c) On a speed–time graph, what does each of these show: a straight rising line; a rising curve that gets flatter; a flat line; a straight falling line? (d) A lorry slows from 25 m/s to 10 m/s in 5.0 s. Calculate its acceleration and state its deceleration. (e) Name the force between brake pads and a brake disc, and say what it does to the disc. (f) State the acceleration of free fall near the Earth, and say how the speed of a falling stone changes in each second when the air hardly slows it.
Acceleration and its unit
The runner's acceleration
What the four shapes show
The lorry's acceleration and deceleration
The force in brakes and what it does
Free fall
2. state / calculate / sketch / explain
Keep the lesson closed. (a) What is drag, and what is drag in air called? (b) Give two things that make the drag on a moving object bigger. (c) A ball sinks through water at a steady speed, taking 0.80 s for every 0.20 m. Calculate its speed. (d) State what is meant by terminal velocity, and compare the forces on a falling object when it reaches it. (e) On paper, sketch on the same axes the speed–time graphs of an object falling with and without air resistance. (f) A skydiver opens her parachute. Describe what happens to her speed afterwards, and explain why.
Drag and its name in air
Two things that make drag bigger
The ball's speed
Terminal velocity and the forces
Your sketch: describe both lines
After the parachute opens