Physics Review

A student sets up the apparatus shown in the diagram to find the centre of mass of the card.

The student makes sure that the card, the string and the bob are all at rest.

What should the student do next?

• Mark a horizontal line on the card level with the middle of the string.

• Mark the line of the string on the card.

• Pull the bob on the string to one side and release it.

• Replace the bob with a heavier bob.

A car moves in a circular path as it turns a corner on a horizontal road.

The car moves at constant speed.

Which description of the forces acting on the car is correct?

• All the forces are balanced as the car is moving at constant speed.

• The forces are unbalanced and the resultant force acts away from the centre of the circle.

• The forces are unbalanced and the resultant force acts towards the centre of the circle.

• The forces are unbalanced and the resultant force is in the direction of travel of the car.

The diagram shows a lorry moving on a straight road.

The arrows represent the horizontal forces acting on the lorry.

These forces act along the same straight line.

Calculate the size of the resultant horizontal force on the lorry.

The diagram shows three horizontal forces acting on a car as it moves along a straight road.

The horizontal forces act along the same straight line.

Calculate the size of the resultant horizontal force on the car.

The mass of an empty beaker is 400 g.

Calculate the weight of the empty beaker in newtons.

The diagram shows a beaker containing liquid on a top pan balance.

The mass of the empty beaker is 400g.

Using the information in the diagram, determine the mass of the liquid in the beaker.

The diagram shows a beaker containing liquid on a top pan balance.

The mass of the empty beaker is 400g.

The beaker contains 750cm³ of liquid.

Using this information, calculate the density (g/cm³) of the liquid.

Here are descriptions of four situations.

Indicate the situations in which work is done.

• A child is sitting at the top of the stairs.

• A picture is hanging on a wall.

• A student is stretching a spring.

• A person is moving a chair.

The diagram shows an archer pulling the string of a bow.

The archer uses a force of 120N. The force acts on an area of 0.5cm² on the archer’s fingers. Calculate the pressure (N/cm²) on the archer’s fingers.

During part of a race, a skier travels a distance of 200 m in a time of 6.4 s.

Calculate the average speed of the skier.