VCE Physics - Random Exam Revision 1

The aim of darts is to hit the bullseye at the centre of a dartboard. Four darts players (A, B, C and D) each threw three darts. The results of their throws are shown.

Which one of the players produced a set of attempts that could be described as being precise but inaccurate?

_{VCAA 2021}

• Player A

• Player B

• Player C

• Player D

Answer explanation

‘Precise but inaccurate’ suggests the results will be clustered tightly but away from the true value (bullseye)

The diagram below shows the electric field lines between two charges of equal magnitude.

The best description of the two charges is that the;

_{VCAA 2020}

• charges are both positive

• charges are both negative.

• charges can be either both positive or both negative.

• left-hand charge is positive and the right-hand charge is negative.

Answer explanation

Field lines show repulsion so both charges are the same. The field lines originate from the charges so they are both positive

Magnetic and gravitational forces have a variety of properties. Referring to the diagram, which option best describes the attraction/repulsion properties of magnetic and gravitational forces?

_{VCAA 2019}

• A

• B

• C

• D

Answer explanation

Magnetic forces can be attractive or repulsive, whereas gravitational forces can only be attractive.

An ultralight aeroplane of mass 500 kg fl ies in a horizontal straight line at a constant speed of 100 m s–1. The horizontal resistance force acting on the aeroplane is 1500 N. Which one of the following best describes the magnitude of the forward horizontal thrust on the aeroplane?

_{VCAA 2019}

• 1500 N

• slightly less than 1500 N

• slightly more than 1500 N

• 5000 N

Answer explanation

Constant speed implies that F_thrust = F_drag.

A straight wire carries a current of 10 A. Which one of the following diagrams best shows the magnetic field associated with this current?

_{VCAA 2018}

• 
• 
• 
• 

Answer explanation

Right-hand grip rule. Thumb up, fingers indicate direction of field.

Four students are pulling on ropes in a four-person tug of war. The relative sizes of the forces acting on the various ropes are FW = 200 N, FX = 240 N, FY = 180 N and FZ = 210 N. The situation is shown in the diagram.

Which one of the following best gives the magnitude of the resultant force acting at the centre of the tug-of-war ropes?

_{VCAA 2018}

• 28.3 N

• 30.0 N

• 36.1 N

• 50.0 N

Answer explanation

𝐹 = √(200−180) ² + (240−210) ²

𝐹 = 36.1 N

A model car of mass 2.0 kg is propelled from rest by a rocket motor that applies a constant horizontal force of 4.0 N, as shown below. Assume that friction is negligible.

Which one of the following best gives the magnitude of the acceleration of the model car?

_{VCAA 2017}

• 0.50 m s^–2

• 1.0 m s^–2

• 2.0 m s^–2

• 4.0 m s^–2

Answer explanation

𝐹 = 𝑚𝑎

4 = 2𝑎

𝑎 = 2 𝑚 𝑠 ⁻²

A model car of mass 2.0 kg is propelled from rest by a rocket motor that applies a constant horizontal force of 4.0 N, as shown below. Assume that friction is negligible.

Which one of the following best gives the magnitude of the impulse given to the car by the rocket motor in the first 5.0 s?

_{VCAA 2017}

• 4.0 N s

• 8.0 N s

• 20 N s

• 40 N s

Answer explanation

𝐼 = 𝐹𝑡

𝐼 = 4 × 5

𝐼 = 20 𝑁 s

A model car of mass 2.0 kg is propelled from rest by a rocket motor that applies a constant horizontal force of 4.0 N, as shown below. Assume that friction is negligible.

With the same rocket motor, the car accelerates from rest for 10 s. Which one of the following best gives the final speed?

_{VCAA 2017}

• 6.3 m s^–1

• 10 m s^–1

• 20 m s^–1

• 40 m s^–1

Answer explanation

𝑣 = 𝑢 + 𝑎𝑡

𝑣 = 0 + 2 × 10

𝑣 = 20 𝑚 𝑠 ⁻¹

On average, the sun emits 3.8 × 10²⁶ J of energy each second in the form of electromagnetic radiation, which originates from the nuclear fusion reactions taking place in the sun’s core. The corresponding loss in the sun’s mass each second would be closest to

_{VCAA 2017}

• 2.1 × 10⁹ kg

• 4.2 × 10⁹ kg

• 8.4 × 10⁹ kg

• 2.1 × 10¹² kg

Answer explanation

𝐸 = 𝑚𝑐 ²

3.8 × 10²⁶ = 𝑚 × (3 × 10⁸ ) ²

𝑚 = 4.2 × 10⁹ kg