The percentage errors in the measurement of length and time period of a simple pendulum are 1% and 2% respectively. Then the maximum error in the measurement of acceleration due to gravity is
8 %
3 %
5 %
6 %
A body is falling freely under gravity. The distances covered by the body in first, second and third minute of its motion are in the ratio
1 : 4 : 9
1 : 2 : 3
1 : 3 : 5
1 : 5 : 6
C.
1 : 3 : 5
Distance covered in a particular time is
Hence, the required ratio is
A bullet fired into a fixed wooden block loses half of its velocity after penetrating 40 cm. It comes to rest after penetrating a further distance of
A ball A is thrown up vertically with a speed u and at the same instant another ball B is released from a height h. At time t, the speed of A relative to B is
u
2u
u − gt
A bullet is to be fired with a speed of 2000 ms-1 to hit a target 200 m away on a level ground. If g = 10 ms-2, the gun should be aimed
directly at the target
5 cm below the target
5 cm above the target
2 cm above the target
The resultant of two vectors and is . If the magnitude of is doubled, the new resultant becomes perpendicular to . Then the magnitude of is
P + Q
Q
P
A motor car is moving with a speed of 20 ms-1 on a circular track of radius 100 m. If its speed is increasing at the, rate of 3 ms-1, its resultant acceleration is
3 ms-2
5 ms-2
2.5 ms-2
3.5 ms-2
A stationary body of mass 3 kg explodes into three equal pieces. Two of the pieces fly off in two mutually perpendicular directions, one with a velocity of ms-1 and the other with a velocity of ms-1. If the explosion occurs in 10-4 s, the average force acting on the third piece in newton is
A mass of 1 kg is just able to slide down the slope of an inclined rough surface when the angle of inclination is 60°. The minimum force necessary to pull the mass up the inclined plane (g = 10 ms-2) is
14.14 N
17.32 N
10 N
16.66 N