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A-Level CAIE Physics 3 2 Non Uniform Motion Question Bank

Practice A-Level CAIE Physics 3 2 Non Uniform Motion questions by syllabus topic with past-paper context, marks, difficulty and question previews on Eduninja.

10 matching questions ยท Open interactive library

Question 1

1

A sphere of radius 2.1 mm falls with terminal (constant) velocity through a liquid, as shown in Fig. 1.1. Three forces act on the moving sphere. The weight of the sphere is \(7.2 \times 10^{-4} \mathrm{~N}\) and the upthrust acting on it is \(4.8 \times 10^{-4} \mathrm{~N}\). The viscous force \(F_{\mathrm{V}}\) acting on the sphere is given by where r is the radius of the sphere, v is its velocity and k is a constant. The value of k in SI units is 17 .

structured8 marks

Question 1(c)

1(c)

8 marks

Question 1(c)(ii)

1(c)(ii)

Determine the magnitude of the terminal (constant) velocity of the sphere.

Mediumstructured8 marks

Answer

\[ \begin{aligned} F_{\mathrm{V}} =7.2 \times 10^{-4}-4.8 \times 10^{-4} =2.4 \times 10^{-4}(\mathrm{~N}) \end{aligned} \] C1 \[ \begin{aligned} \text { velocity } =2.4 \times 10^{-4} /\left(17 \times 2.1 \times 10^{-3}\right) =6.7 \times 10^{-3} \mathrm{~m} \mathrm{~s}^{-1} \end{aligned} \] A1 Question Marks

Question 1

1

4 marks

Question 1(b)

1(b)

The variation with time t of vertical speed v of a parachutist falling from an aircraft is shown in Fig. 1.1.

structured4 marks

Question 1(b)(ii)

1(b)(ii)

Explain the variation of the resultant force acting on the parachutist from t=0 (point A) to \(t=15 \mathrm{~s}\) (point C).

Mediumstructured3 marks

Answer

resultant force = weight - frictional force B1 frictional force increases with speed B1 at start frictional force =0 / at end weight = frictional force B1 [3]

Question 1(b)(iii)

1(b)(iii)

Describe the changes to the frictional force on the parachutist 1. at \(t=15 \mathrm{~s}\) (point C ), 2. between \(t=15 \mathrm{~s}\) (point C ) and \(t=22 \mathrm{~s}\) (point E).

Mediumstructured1 marks

Answer

1. frictional force increases B1 [1] 2. frictional force (constant) and then decreases B1 [1]

Question 1

1

2 marks

Question 1(b)

1(b)

Fig. 1.1 shows a turbine that is used to generate electrical power from the wind. The power P available from the wind is given by where L is the length of each blade of the turbine, \(\rho\) is the density of air, v is the wind speed, C is a constant.

structured2 marks

Question 1(b)(iii)

1(b)(iii)

Suggest two reasons why the electrical power output of the turbine is less than the power available from the wind. 1

Mediumstructured2 marks

Answer

not all kinetic energy of wind converted to kinetic energy of blades B1 generator/conversion to electrical energy not 100\% efficient/heat produced in generator / bearings etc (there must be cause of loss and where located)

Question 1

1

2 marks

Question 1(c)

1(c)

In practice, the planet in (b) does have an atmosphere that causes a viscous force to act on the moving rock. State and explain the variation, if any, in the resultant force acting on the rock as it moves vertically upwards.

Mediumstructured2 marks

Answer

speed/velocity decreases so viscous force decreases B1 viscous force decreases (and weight constant) so resultant force decreases B1

Question 3

3

A football is kicked so that it moves vertically upwards through the air. What is the variation in the air resistance and the resultant force acting on the ball as it moves vertically upwards?

Mediummcq1 marks

Answer

A

Question 2

2

A sphere floats in equilibrium on the surface of sea water of density \(1050 \mathrm{~kg} \mathrm{~m}^{-3}\), as shown in Fig. 2.1.

structured8 marks

Question 2(b)

2(b)

The sphere is now held so that its entire volume is below the surface of the water. The sphere is then released.

structured3 marks

Question 2(b)(ii)

2(b)(ii)

The sphere accelerates upwards but remains entirely below the surface of the water. State and explain what happens to the acceleration of the sphere as its velocity begins to increase.

Mediumstructured3 marks

Answer

the (downward) drag / viscous force increases (with speed) M1 resultant force decreases (as upthrust and weight remain the same) M1 acceleration decreases (as its velocity increases) A1

Question 2

2

2 marks

Question 2(c)

2(c)

The diver in (b) enters the water and decelerates.

structured2 marks

Question 2(c)(i)

2(c)(i)

Describe and explain the variation of the viscous drag force acting on the diver in the water as he moves downwards.

Mediumstructured2 marks

Answer

(As the diver moves down their) speed decreases B1 (So) viscous force / drag (force) decreases B1

Question 2

2

A ball is thrown from a point P , which is at ground level, as illustrated in Fig. 2.1. The initial velocity of the ball is \(12.4 \mathrm{~m} \mathrm{~s}^{-1}\) at an angle of \(36^{\circ}\) to the horizontal. The ball just passes over a wall of height h. The ball reaches the wall 0.17 s after it has been thrown.

structured2 marks

Question 2(b)

2(b)

A second ball is thrown from point P with the same velocity as the ball in (a). For this ball, air resistance is not negligible. This ball hits the wall and rebounds. On Fig. 2.1, sketch the path of this ball between point P and the point where it first hits the ground.

Mediumstructured2 marks

Answer

smooth curve with ball hitting wall below original B1 smooth curve showing rebound to ground with correct reflection at wall B1

Question 2

2

2 marks

Question 2(c)

2(c)

The student in (b) takes a second photograph starting at the same position on the scale. The ball has the same radius but is less dense, so that air resistance is not negligible. State and explain the changes that will occur in the photograph.

Mediumstructured2 marks

Answer

(air resistance) means ball's speed/acceleration is less M1 length of image is shorter A1

Question 2

2

A ball is thrown horizontally from the top of a building, as shown in Fig. 2.1. The ball is thrown with a horizontal speed of \(8.2 \mathrm{~ms}^{-1}\). The side of the building is vertical. At point P on the path of the ball, the ball is distance x from the building and is moving at an angle of \(60^{\circ}\) to the horizontal. Air resistance is negligible.

structured2 marks

Question 2(b)

2(b)

The path of the ball in (a), with an initial horizontal speed of \(8.2 \mathrm{~m} \mathrm{~s}^{-1}\), is shown again in Fig. 2.2. On Fig. 2.2, sketch the new path of the ball for the ball having an initial horizontal speed

structured2 marks

Question 2(b)(ii)

2(b)(ii)

equal to \(8.2 \mathrm{~m} \mathrm{~s}^{-1}\) but with air resistance (label this path A ).

Mediumstructured2 marks

Answer

smooth path curved and below given path hits ground at steeper angle