NCEA Level 3 Physics Revision Equation Test 1

Some of these answers require you to remember Level 2 Physics and/or common sense.

(Take g = 9.8 ms^-2, h = 6.63 x 10³⁴ Js, c = 3 x 10⁸ m s^-1, e_o= 8.85 x 10^-12 N^-1m^-2C², e_r= 1 for air).

Do you understand what you have to do?

• Yes

• No

• Nothing ever makes sense

• 42

A mass A of 6 kg moving with a velocity of 5 ms^-1 collides with a mass B of 8 kg moving in the opposite direction at 3 ms^-1. Calculate the final velocity if the masses stick together on impact.

• 0 ms^-1

• 0.42 ms^-1

• 3.86 ms^-1

• 6 ms^-1

An object of mass 2.0 kg starts from rest and slides down a friction-less incline at an angle of 30^o to the horizontal. If it slides 2.5 m down the plane, what will be its velocity?

• 3.5 ms^-1

• 4.9 ms^-1

• 7 ms^-1

• 14 ms^-1

A wheel has a radius of 0.3 m. It rotates with an angular velocity of 12 s^-1. What is the linear velocity of a point on the rim of the wheel?

• 3.6 ms^-1

• 12 ms^-1

• 36 ms^-1

• 40 ms^-1

Calculate the capacitance of a pair of parallel plates of area 0.025 m² if they are separated by a piece of perspex 0.1 mm thick. Take the relative permittivity of perspex to be 3.5.

• 1.9 x 10^-8 F

• 7.7 x 10^-8 F

• 2.2 x 10^-9 F

• 7.7 x 10^-9 F

What is the resistance of a 240 V, 100 W light bulb?

• 0.41 ohms

• 2.4 ohms

• 5.76 ohms

• 576 ohms

A 5 kg mass extends a spring by 0.50 m. What is the spring constant of the spring?

• 2.5 N m^-1

• 9.8 N m^-1

• 98 N m^-1

• 980 N m^-1

How far apart are two parallel plates in air, area 0.50 m² and capacitance 1.5 micro Farads?

• 3.33 x 10⁶ m

• 2.95 x 10^-3 m

• 2.95 x 10^-6 m

• 5.90 x 10^-6 m

A yo-yo, initially at rest, is allowed to fall from a finger. The yo-yo drops with constant linear acceleration. After 1.40 seconds it has fallen 1.20 m and reached an angular velocity of 4090 revolutions per minute. What angle (in radians) does the yo-yo turn through during the fall of 1.20 m?

• 13 radians

• 40.9 radians

• 47.7 radians

• 1432 radians

How much torque is needed to bring a flywheel with moment of inertia 0.2 kg m² rotating at 50 rad s^-1 to rest in 20 seconds?

• 0.5 N m

• 1 N m

• 5 N m

• 5000 N m