Atmospheric pressure

In a world record attempt, a skydiver jumped from a height of 40 km above the Earth.

Figure 6 shows an incomplete free-body diagram for the skydiver a few seconds after the start of the jump.

Figure 6

The skydiver has not reached terminal velocity.

Complete the free-body diagram in Figure 6.

During the first 2.5 minutes the mean acceleration of the skydiver was 0.64 m/s².

The initial velocity of the skydiver was 0 m/s.

Calculate the velocity of the skydiver 2.5 minutes after the start of the jump.

Use the Physics Equations Sheet.

The skydiver accelerated until reaching terminal velocity.

Explain why the skydiver reached terminal velocity.

Explain why the atmospheric pressure acting on the skydiver increased as the skydiver fell.

The skydiver opened his parachute.

A few seconds after opening the parachute, the resultant vertical force on the skydiver was 240 N upwards.

The wind caused a resultant horizontal force of 200 N to the left on the skydiver.

Draw a vector diagram to determine the resultant force on the skydiver.

Figure 25 shows the route an aeroplane takes as it travels from an airport terminal to the runway. Figure 25 has been drawn to scale.

Determine the magnitude of the aeroplane’s displacement from the start point to the finish point on Figure 25.

Figure 26 shows the direction of the horizontal forces acting on the aeroplane as it moves in a straight line towards the runway.

Determine the magnitude of the resultant horizontal force on the aeroplane.

Describe the motion of the aeroplane as it moves towards the runway.

Air resistance and friction are contact forces. Give one other example of a contact force.

The aeroplane stops for a short time and then accelerates along the runway. Figure 27 shows a distance–time sketch-graph for this stage of the journey.

Draw the velocity–time sketch-graph for this stage of the journey on Figure 28.

The aeroplane takes off from the runway, so its height above the ground increases. Figure 29 shows how atmospheric pressure varies with the height of the aeroplane above the ground.

Estimate the atmospheric pressure when the height of the aeroplane above the ground is 10 km.

What happens to the air surrounding the aeroplane as the height of the aeroplane above the ground increases? Tick (✓) one box.

Figure 3 shows the route an aeroplane takes as it travels from an airport terminal to the runway. Figure 3 has been drawn to scale.

Determine the magnitude of the aeroplane’s displacement from the start point to the finish point on Figure 3.

Figure 4 shows the direction of the horizontal forces acting on the aeroplane as it moves in a straight line towards the runway.

Determine the magnitude of the resultant horizontal force on the aeroplane.

Describe the motion of the aeroplane as it moves towards the runway.

Air resistance and friction are contact forces. Give one other example of a contact force.

The aeroplane stops for a short time and then accelerates along the runway. Figure 5 shows a distance–time sketch-graph for this stage of the journey.

Draw the velocity–time sketch-graph for this stage of the journey on Figure 6.

The aeroplane takes off from the runway, so its height above the ground increases. Figure 7 shows how atmospheric pressure varies with the height of the aeroplane above the ground.

Estimate the atmospheric pressure when the height of the aeroplane above the ground is 10 km.

What happens to the air surrounding the aeroplane as the height of the aeroplane above the ground increases? Tick (✓) one box.

The Earth is surrounded by an atmosphere.

The radius of the Earth is 6400 km.

Which of the following could be an approximate depth of the Earth’s atmosphere?

Tick (✓) one box.

What state of matter is most of the Earth’s atmosphere?

Tick (✓) one box.

Figure 12 shows how atmospheric pressure varies with height above sea level.

The highest point above sea level in England is the top of a mountain called Scafell Pike.

The height above sea level of Scafell Pike is 978 m.

Determine the atmospheric pressure at the top of Scafell Pike.

Use Figure 12.

Determine the difference between the atmospheric pressure at sea level and at the top of Scafell Pike.

Use Figure 12 and your answer from Question 06.3

A student climbs Scafell Pike.

Why does the atmospheric pressure decrease as the student climbs higher?

Tick (✓) two boxes.

Figure 13 shows a mountain lake.

The lake has a surface area of 2000 m².

Atmospheric pressure exerts a force of 188 000 000 N on the surface of the lake.

Calculate the atmospheric pressure at the surface of the lake.

Use the equation:

An aeroplane is 4000 m above the Earth’s surface. A skydiver jumps from the aeroplane and falls vertically. Figure 15 shows the distance the skydiver falls during the first 12 seconds after jumping.

Figure 16 shows part of the free body diagram for the skydiver three seconds after jumping. Complete the free body diagram for the skydiver.

Explain the changing motion of the skydiver in terms of the forces acting on the skydiver.

Use Figure 15 to determine the speed of the skydiver between 7 seconds and 12 seconds.

In 2012 a skydiver jumped from a helium balloon 39 000 metres above the Earth’s surface. The skydiver reached a maximum speed of 377 m/s Jumping from 39 000 metres allowed the skydiver to reach a much higher speed than a skydiver jumping from 4000 metres. Explain why.