A helicopter flies from a city A to B. The line joining A and B is along North-South direction and its length is 100 km. The speed of the helicopter is kept 100 km/h and the wind blows from West to East with a speed of 60 km/h. The time taken by the helicopter is
(1) 0.75 h
(2) 1.0 h
(3) 1.25 h
(4) 1.33 h
Four particles lie initially at the corners of a square of side length L. All the particles start to move with speed v. A moves towards B, B moves towards C, C moves towards D and D moves towards A. The distance covered by a particle till they meet is
(1)
(2) L
(3)
(4) 2L
A boat can move with a maximum speed of 10 m/s in still water. If the speed of river water is 5 m/s, then in how much minimum time the boat can cross the river of width 500 m?
(1) s
(2) 50 s
(3) 100 s
(4) 150 s
A particle is thrown at an angle of projection = 45° with speed u. The average velocity of the particle during its ground to ground flight is
1.
2.
3.
4. 0
The raindrops are falling with speed \(v\) vertically downwards and a man is running on a horizontal road with speed \(u.\) The magnitude of the velocity of the raindrops with respect to the man is:
1. \(v-u\)
2. \(v+u\)
3. \(\sqrt{{v}^2 + {u}^2 \over 2}\)
4. \(\sqrt{{v}^2 + {u}^2}\)
A bomb is dropped from an aeroplane flying horizontally. The path of the bomb as seen by the pilot will be (neglect air friction)
(1) A straight line
(2) A parabola
(3) An ellipse
(4) A hyperbola
The range of a bullet fired from a gun at an angle with the horizontal is the same as the range of another bullet fired from that gun at an angle with the horizontal. Then,
1.
2.
3.
4.
A boy runs on a circular track of radius \(R\) (in km) with a speed of \(\dfrac{πR}{2}\) km/h in the clockwise direction for \(3\) h and then with \(πR\) km/h in the anticlockwise direction for \(1\) h. The magnitude of his displacement will be:
1. \(\dfrac{πR}{2}\)
2. \(\dfrac{R}{\sqrt{2}}\)
3. \(\dfrac{3πR}{2}\)
4. \(\sqrt{2}R\)
Two projectiles P and Q are projected with the same speed at angles 60° and 30° with horizontal on level ground, then: [R = Range, T = Time of flight, H = Maximum height]
(1)
(2)
(3)
(4) All of these
A body is projected with the same speed at two different angles covers the same horizontal distance R. If are two times of flights, then R is equal to :
1.
2.
3.
4.