GCSE Edexcel Physics Kinetic Energy: Figure 15 shows a ‘Mars rover’ d

Figure 15 shows a ‘Mars rover’ descending to the surface of the planet Mars - Edexcel - GCSE Physics - Question 7 - 2022 - Paper 1

Question 7

Figure 15 shows a ‘Mars rover’ descending to the surface of the planet Mars. Mass of rover = 1100 kg Gravitational field strength on Mars = 3.7 N/kg (i) Calculate... show full transcript

Worked Solution & Example Answer:Figure 15 shows a ‘Mars rover’ descending to the surface of the planet Mars - Edexcel - GCSE Physics - Question 7 - 2022 - Paper 1

Step 1

(i) Calculate the change in gravitational potential energy of the rover as it descends from position P to position Q.

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Answer

To calculate the change in gravitational potential energy (GPE), use the formula:

$\text{GPE} = mgh$

Where:

m = mass of the rover = 1100 kg
g = gravitational field strength = 3.7 N/kg
h = change in height = 1.80 km - 1.60 km = 0.20 km = 200 m

Substituting the values:

$\text{GPE} = 1100 \times 3.7 \times 200$

Calculating:

$\text{GPE} = 1100 \times 3.7 \times 200 = 814000 \text{ J}$

Expressing the answer to 2 significant figures:

$\text{change in gravitational potential energy} = 8.1 \times 10^5 \text{ J}$

Step 2

(ii) Use data from Figure 15 to calculate the change in kinetic energy of the rover as it descends from position P to position Q.

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Answer

To calculate the change in kinetic energy (KE), use the formula:

$\text{KE} = \frac{1}{2}mv^2$

Where:

m = mass of the rover = 1100 kg
v = initial speed at position P = 88 m/s

Calculating the KE at position P:

$\text{KE}_P = \frac{1}{2} \times 1100 \times (88)^2$

Calculating:

$\text{KE}_P = 0.5 \times 1100 \times 7744 = 4268800 \text{ J}$

The final speed at position Q is 0 m/s, so:

$\text{KE}_Q = 0$

Now, the change in kinetic energy:

$\text{change in KE} = \text{KE}_Q - \text{KE}_P$

Therefore:

$\text{change in KE} = 0 - 4268800 = -4268800 \text{ J}$

Figure 15 shows a ‘Mars rover’ descending to the surface of the planet Mars - Edexcel - GCSE Physics - Question 7 - 2022 - Paper 1

Worked Solution & Example Answer:Figure 15 shows a ‘Mars rover’ descending to the surface of the planet Mars - Edexcel - GCSE Physics - Question 7 - 2022 - Paper 1

(i) Calculate the change in gravitational potential energy of the rover as it descends from position P to position Q.

(ii) Use data from Figure 15 to calculate the change in kinetic energy of the rover as it descends from position P to position Q.

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