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.
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.
A car of mass 800kg attains a speed of 25m/s in 20 secs. The power developed in the engine is
1 . 25 x 104 W
2 . 50 x 104 W
1 . 25 x 106W
2 . 50 x 106 W
Correct answer is B
Power = Force x \(\frac{distance}{time}\) = \(\frac{m(v - u)}{t} \times v\)
\(\frac{800(25 - 0)}{20} \times 25\)
= 2.5 x 10\(^{4}\) watts
5 J
10 J
15 J
20 J
Correct answer is C
Height h = 1/2 (U\(^2\)/g) = 10\(^2\)/20 = 5m
Energy before hitting ground is = P.E at the height of 5m.
P.E = mgh = 0.1 x 10 x 10= 10 J
K.E = 1/2 MV\(^2\) = 5J
T.E = K.E + P.E = 5 + 10 = 15J
50 J
100 J
150 J
200 J
Correct answer is A
From principle of conservation of linear momentum,
(0.05 x 200) + (0.95 x 0) = (0.05 + 0.95) x V (since collision is inelastic).
10 + 0 = V
Thus V = 10m/s.
Recall Kinetic Energy = \(\frac{1}{2} mv^2\)
\(\therefore\) K.E = 1/2 (0.05 + 0.95) x 10\(^2\)
K.E = 1/2 (1 x 100) = 50 J.
2 N
20 N
200 N
400 N
Correct answer is B
Centripetal Force (F\(_c\)) = \(\frac{mv ^2}{r}\)
= \(mω^2r\)
(Since V = ωr)
F = 100 x 0.2
F =20 N
1 : 4
2 : 1
2 : 3
2 : 5
Correct answer is C
Let the forces be F1, and F2.
F1 = m1 a1 = 3 x 2 = 6N
F2 = m2 a2 = 1 x 9 = 9N
F1 : F2 = 6:9 = 2:3
Thus ratio of forces is 2: 3