Pass Check: Forces & Energy
Forces are pushes or pulls; resultant force causes acceleration (F = ma).
Scalar
A quantity with magnitude only, e.g. speed or distance.
Vector
A quantity with magnitude and direction, e.g. velocity or force.
Resultant force
The single force that has the same effect as all forces acting on an object combined.
Momentum
The product of an object's mass and velocity; a conserved vector quantity.
Quick check
Mixed quiz
1. Complete the sentence: Why is a velocity-time graph with a curve of decreasing gradient described as ______.
2. Why does a longer collision time reduce injury?
3. Which is an energy store?
4. Calculate the power of a 700 N force moving an object 15 m in 5 s.
5. What is the unit of force?
6. What is elastic deformation?
7. Calculate the gravitational potential energy gained lifting 20 kg by 3 m (g = 10).
8. Why is stopping distance greater on a wet road?