Example Exam Questions
- Can you explain why a car reaches a terminal velocity?
At first the driving force is greater than the air resistance so the car speeds up. As it speeds up, the air resistance increases. Eventually air resistance equals the driving force, so there is no acceleration.
- What is resultant force?
It is the overall force acting on an object.
- What is terminal velocity?
It is when an object can no longer accelerate and so reaches its highest velocity. Air resistance = the force acting on an object.
- Complete the sentence:
Velocity is speed but it also has________.
Velocity is speed but also has direction.
- Give two examples of momentum.
Collisions and explosions.
- Describe what happens when two objects explode.
The momentum of each object is the same and they move in opposite directions.
- What is meant by the term momentum is conserved?
The total momentum after the collision is equal to the total momentum before the collision
- What do crumple zones do?
They increase the time of impact so even though there is the same change in momentum, the impact force is smaller. Therefore, injury is less likely.
- What is meant by current?
It is the rate of flow of charge.
- Why do metals conduct electricity?
They contain free delocalised electrons which move about freely and carry charge.
- How do you safely discharge a charged conductor?
Provide a conducting path between the object and the ground.
- Describe what a photocopier does.
Photocopiers with a metal drum-drum is positively charged until light falls on it. Light is reflected off the paper onto the drum. The areas of black do…