OAT Physics Principles 4

Question 1

A block of mass 5 kg slides down a frictionless incline angled at 30°. What is its acceleration? (g = 10 m/s²)

Accepted Answer

5 m/s²

Answer

Acceleration along the incline = g sin 30° = 10 × 0.5 = 5 m/s².

Question 2

Two resistors of 6 Ω and 3 Ω are connected in parallel. What is their combined resistance?

Accepted Answer

2 Ω

Answer

1/R = 1/6 + 1/3 = 1/6 + 2/6 = 3/6 → R = 2 Ω.

Question 3

Which of the following quantities is conserved in all types of collisions?

Accepted Answer

Momentum only

Answer

Momentum is always conserved in collisions; kinetic energy is conserved only in perfectly elastic collisions.

Question 4

A glass lens immersed in water has a lower refracting power than in air. This is because:

Accepted Answer

The refractive index difference between glass and water is smaller than between glass and air

Answer

Lens power depends on the relative refractive index (n_glass/n_medium); since n_water ≈ 1.33, the contrast with glass is less than in air (n = 1.0).

Question 5

What happens to the period of a simple pendulum if its length is quadrupled?

Accepted Answer

It doubles

Answer

T = 2π√(L/g); quadrupling L increases √L by a factor of 2, so the period doubles.

OAT - Optometry Admission Test Practice Test