CBSE
n balls each of mass m impinge elastically each second on a surface with velocity v. The average force experienced by the surface will be
2nmv
nmv
4nmv
Two blocks of masses 2 kg and 5 kg are connected by an ideal string passing over a pulley. The block of mass 2 kg is free to slide on a surface inclined at an angle of 30° with the horizontal whereas 5 kg block hangs freely. The tension (T) in the string is
48.56 N
72.22 N
32.56 N
24.65 N
The upper half of an inclined plane with inclination is perfectly smooth, while the lower half is rough. A body starting from rest at the top will again come to rest at the bottom, if the coefficient of friction for the lower half is given by
2 sin
2 cos
2 tan
tan
The angle to which a cyclist bends when he covers a circular path of 34.3 m in s is
20°
30°
60°
45°
The minimum velocity (in ms-1) with which a car driver must traverse a flat curve of radius 150 m and coefficient of friction to avoid skidding is
60
30
15
25
A string of negligible mass going over a clamped pulley of mass m supports a block of mass M as shown in the figure. The force on the pulley by the clamp is given by
A gun of mass M fires a bullet of mass m with velocity v. Then, the recoil speed of the gun will be
A body of mass 3 kg is acted on by a force which varies as shown in the graph. The momentum acquired is given by
zero
5 N-s
30 N-s
50 N-s
If the coefficient of static friction between the tyres and road is 0.5, what is the shortest distance in which an automobile can be stopped when travelling at 72 kmh-1 ?
50 m
60 m
40.8 m
80.16 m
A body of mass 5 kg moves on a straight path as a function of time x = t3 − 12t. The force on the body at t = 5s will be
100 N
150 N
120 N
130 N