Physics Questions and Answers

If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.

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1,801.

A plane inclined at 30^o to the horizontal has an efficiency of 50%. Calculate the force parallel to the plane required to push a load of 120N uniformly upon the plane

50.0N

120.0N

200.0N

240N

View answer & explanation

Correct answer is B

V.R = \(\frac{1}{sin\theta} = \frac{1}{sin 30} = 2\)

M.A = \(\frac{E \times V.R}{100} = \frac{50 \times 2}{100} = 1\)

Effort = \(\frac{load}{M.A} = \frac{120}{1} = 120N\)

1,802.

A car of mass 800kg moves from rest on a horizontal track and travels 60m in 20s with uniform acceleration. Assuming there were no frictional forces, calculate the accelerating force

240.0N

800.0N

1600.00N

2400.0N

View answer & explanation

Correct answer is A

S = at + \(\frac{1}{2} at^2\)

60 = 0 x 20 + \(\frac{1}{2}\) x a x 20

a = \(\frac{3}{10}\)m/s²

F = ma = 800 x \(\frac{3}{10} = 240N\)

1,803.

An external force of magnitude 100N acts on a particle of mass 0.15kg for 0.03s. Calculate the change in the speed of the particle

50ms^-1

25ms^-1

20ms^-1

5ms^-1

View answer & explanation

Correct answer is C

a = \(\frac{F}{m} = \frac{100}{0.15} = 666.7\)

v = u + at

= 0 + 66.7 x 0.03

= 20m/s²

1,804.

A block of mass 4.0kg causes a spiral spring to extend by 0.16m from its unstretched position. The block is removed and another body of mass 0.50kg is hung from the same spiral spring. If the spring is then stretched and released, what is the angular frequency of the subsequent motion? [g = 10 ms ^-2]

10\(\sqrt 5\) rads^-1

5\(\sqrt 2\) rads^-1

5 rads^-1

\(\sqrt 5\) rads^-1

View answer & explanation

Correct answer is A

K = \(\frac{F}{e} = \frac{4}{0.16} = 250\)

F = \(\frac{1}{T} = \frac{1}{2 \pi \frac{\sqrt{m}}{k}}\)

= \(\frac{1}{2 pi \frac{\sqrt{0.5}}{250}}\)

= 10\(\sqrt{5}\)