Gravity and weight

Which row of the table shows the correct units of weight and of mass?

State the name of a piece of equipment that can be used to measure mass.

Figure 9 shows the two forces acting on a beach ball as it falls through the air.

The resultant of these two forces is 0.92 N downwards.

The mass of the beach ball is 0.25 kg.

Calculate the acceleration of the beach ball as it falls.

Use the equation

acceleration =_........ m / s²

Calculate the size of the air resistance force on the beach ball.

Some students are investigating forces.

They use a newton meter to keep a trolley stationary on a sloping runway, as shown in Figure 10.

They measure the force needed to keep the trolley stationary on the sloping runway.

They do this at four different places on the runway.

When the height, h, of the runway is 0.60 m, their four readings for force are

2.1 N 2.7 N 2.5 N 2.2 N

Calculate the mean value of these forces.

The students then measure values of the force, F, for several different values of h, the height of the runway.

Figure 11 is a graph of F against h.

Use the graph in Figure 11 to determine the value of F when h = 0.80 m.

Determine the gradient of the graph in Figure 11.

gradient =_........ N / m

Figure 1 shows the two forces acting on a beach ball as it falls through the air.

The resultant of these two forces is 0.92 N downwards.

The mass of the beach ball is 0.25 kg.

Calculate the acceleration of the beach ball as it falls.

Use the equation

F = m × a

acceleration =_........ m / s²

Calculate the size of the air resistance force on the beach ball.

Some students are investigating forces.

They use a newton meter to keep a trolley stationary on a sloping runway, as shown in Figure 2.

They measure the force needed to keep the trolley stationary on the sloping runway.

They do this at four different places on the runway.

When the height, h, of the runway is 0.60 m, their four readings for force are

2.1 N 2.7 N 2.5 N 2.2 N

Calculate the mean value of these forces.

The students then measure values of the force, F, for several different values of h, the height of the runway.

Figure 3 is a graph of F against h.

Use the graph in Figure 3 to determine the value of F when h = 0.80 m.

Determine the gradient of the graph in Figure 3.

gradient =_........ N / m

Which of these is a scalar quantity?

A student has some cupcake cases.

One cupcake case is shown in Figure 7.

The student drops a stack of cupcake cases with the base facing downwards, as shown in Figure 8.

(Source: © Elena Schweitzer/Shutterstock)

Figure 8

The speed of the falling stack of cupcake cases depends on the number of cupcake cases in the stack.

The student also has a stop clock and a metre rule.

Describe an investigation to show how the speed of the falling stack of cupcake cases depends on the number of cupcake cases in the stack.

A stack of cupcake cases has a mass of 0.005 kg.

Calculate the weight, in newtons, of the stack of cupcake cases.

Gravitational field strength = 10 N / kg

Use the equation

W = mg

Figure 9 shows a cupcake case that is falling at a constant velocity.

Draw an arrow on Figure 9 to show the force due to air resistance on the cupcake case.

State the value of the acceleration of the cupcake case when it is falling at a constant velocity

A car travels along a straight road.

The car accelerates at 3 m / s² for a time of 7 s.

Calculate the change in velocity of the car.

Use the equation

change in velocity = acceleration × time taken

change in velocity =_........ m / s

Which of these is a scalar quantity?

A student has some cupcake cases.

One cupcake case is shown in Figure 1.

The student drops a stack of cupcake cases with the base facing downwards, as shown in Figure 2.

(Source: © Elena Schweitzer/Shutterstock)

Figure 2

The speed of the falling stack of cupcake cases depends on the number of cupcake cases in the stack.

The student also has a stop clock and a metre rule.

Describe an investigation to show how the speed of the falling stack of cupcake cases depends on the number of cupcake cases in the stack.

A stack of cupcake cases has a mass of 0.005 kg.

Calculate the weight, in newtons, of the stack of cupcake cases.

Gravitational field strength = 10 N / kg

Use the equation

W = mg

Figure 3 shows a cupcake case that is falling at a constant velocity.

Draw an arrow on Figure 3 to show the force due to air resistance on the cupcake case.

State the value of the acceleration of the cupcake case when it is falling at a constant velocity.

Which of these speeds would be normal for a person walking?

Figure 1 shows a block hanging from a spring balance.

Use a word from the box to complete the sentence below.

The quantity measured by the spring balance in Figure 1 is

A toy car has a mass of 0.10 kg. The toy car accelerates at 2.0 m/s².

Calculate the force producing this acceleration. State the unit.

Use the equation

F = m × a

force =_........ unit =_........

Use words from the box to complete the sentences below.

Vectors have size and_........ .

Scalars have only_........ .

The symbol ‘ g ’ can be used to refer to the acceleration due to gravity.

The acceleration due to gravity ‘g’ has the unit of m/s².

‘ g ’ can also have another unit.

Which of these is also a unit for g ?

Two students try to determine a value for g, the acceleration due to gravity.

They measure the time, t, for a small steel ball to fall through a height, h, from rest.

They measure t to be 0.74 s, using a stopwatch.

They measure h to be 2.50 m, using a metre rule.

Calculate a value for g from the students’ measurements.

Use the equation

g =_........ m/s²

They record the time t for two more drops from the same height.

The three values for time t are

0.74 s, 0.69 s, 0.81 s.

Calculate the average value of time t to an appropriate number of significant figures.

average value of time t =_........ s

Explain one way the students could improve their procedure to obtain a more accurate value for g.

A car travelling at 15 m/s comes to rest in a distance of 14 m when the brakes are applied.

Calculate the deceleration of the car. Use an equation selected from the list of equations at the end of this paper.

deceleration =_........ m/s²