A bullet of mass 20 g has an initial speed of just before its starts penetrating a mud wall of thickness 20 cm . If the wall offers a mean resistance of , the speed of the bullet after emerging from the other side of the wall is close to :
The trajectory of a projectile near the surface of the earth is given as . If it were launched at an angle with speed then :
and
and
and
and
A shell is fired from a fixed artillery gun with an initial speed u such that it hits the target on the ground at a distance R from it. If and are the values of the time taken by it to hit the target in two possible ways, the product is:
A particle starts from origin O from rest and moves with a uniform acceleration along the positive x-axis. Identify all figure that corectly represent the motion qualitatively. (a=acceleration, v=velocity,x=displacement,t=time)
(B),(C)
(A)
(A),(B),(C)
(A),(B),(D)
Let and the value of is
-106.5
-99.5
-112.5
-118.5
A particle is moving with speed along the positive x-axis. Calculate the speed of the particle at time(assume that the particle is at the origin at t=0).
Two particles are projected from the same point with the same speed u such that they have the same rang R, but different maximum heights and . Which of the following is correct?
The position vector of a particle changes with time according to the relation . What is the magnitude of the accelaration at ?
The position of a particles as a function of time t , is given by
where a,b,and c are constants . When the particle attains zero acceleration , then its velocity will be :
The stream of a river is flowing with a speed of . A swimmer can swim at a speed of . What should be the direction of the swimmer with respect to the flow of the river to cross the river straight ?
Ship A is sailing towards north-east with velocity km/hr where points east and , north. Ship B is at a distance of 80 km east and 150 km north of Ship A and is sailing towards west at 10 km/hr. A will be at minimum distance from B in :
2.6 hrs.
2.2 hrs.
4.2 hrs.
3.2 hrs.
A particle just clears a wall of height b at a
distance a and strikes the ground at a distance c
from the point of projection. The angle of
projection is
2
A body falling from rest under gravity passes a certain point P. It was at a distance of 400 m from P, 4s prior to passing through P. If g = 10 , then the height above the point P from where the body began to fall is
720
900
320
680