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
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
A particle starts from rest at t = 0 and moves in a straight line with an acceleration as shown in figure. The velocity of the particle at t = 3 s is
2 ms-1
4 ms-1
6 ms-1
8 ms-1
Two cars A and B are moving with same speed of 45 km/h along same direction. If a third car C coming from the opposite direction with a speed of 36 km/h meets two cars in an interval of 5 min, the distance of separation of two cars A and B should be (in km)
6.75
7.25
5.55
8.35
Two trains are moving with equal speed in opposite directions along two parallel railway tracks. If the wind is blowing with speed u along the track so that the relative velocities of the trains with respect to the wind are in the ratio 1 : 2, then the speed of each train must be
3u
2u
5u
4u
Two balls are dropped to the ground from different heights. One ball is dropped 2 s after the other but they both strike the ground at the same time. If the first ball takes 5 s to reach the ground, then the difference in initial heights is (g = 10 ms-2)
20 m
80 m
170 m
40 m
A ball is thrown vertically upwards with a velocity of 25 ms-1 from the top of a tower of height 30 m. How long will it travel before it hits ground ?
6 s
5 s
4 s
12 s
To cover a population of 20 lakh, a transmission tower should have a height (Radius of earth = 6400 km, populatton per square km=1000)
25 m
50 m
75 m
100 m
B.
50 m
Area of region covered =
In 1 km2 = 1000 people