A boat takes two hours to travel 8 km and back in still water. If the velocity of water is 4 km/h, the time taken for going upstream 8 km and coming back is -
A boat crosses a river with a velocity of 8 km/h. If the resulting velocity of boat is 10 km/h then the velocity of river water is –
A boat is rowing in a river at the rate of 4.8 km/hr with respect to river. The river flows at the rate of 6 km/hr. The speed of boat in m/s can be :
Two boats A and B having same speed relative to river are moving in a river. Boat A moves normal to the river current as observed by an observer moving with velocity of river current. Boat B moves normal to the river as observed by the observer on the ground.
A man who can swim at the rate of 2 km/hr (in still river) crosses a river to a point exactly opposite on the other bank by swimming in a direction of 1200 to the flow of the water in the river. The velocity of the water current in km/hr is
A man standing on a road hold his umbrella at 30º with the vertical to keep the rain away. He throws the umbrella and starts running at 10 km/hr. He finds that raindrops are hitting his head vertically, the speed of raindrops with respect to the road will be –
It is raining vertically downwards with a velocity of 3 km h¯¹ . A man walks in the rain with a velocity of 4 kmh¯¹. The rain drops will fall on the man with a relative velocity of
A flag on a bus is fluttering in north direction & wind is blowing in east direction. Then which of the following will be true -
A man wearing a hat of extended length 12 cm is running in rain falling vertically downwards with speed 10 m/s. The maximum speed with which man can run, so that rain drops do not fall on his face (the length of his face below the extended part of the hat is 16 cm) will be :
A man walks in rain with a velocity of 5 kmh¯¹. The rain drops strike at him at an angle of 45° with the horizontal. Velocity of rain if it is falling vertically downward -
Raindrops are falling vertically with a velocity of 10 m/s. To a cyclist moving on a straight road the raindrops appear to be coming with a velocity of 20 m/s. The velocity of cyclist is :
A particle A is at rest and particle B moves in a circle with A at it's centre. The particle A will appear :
A student is standing at a distance of 50metres from the bus. As soon as the bus begins its motion with an acceleration of 1ms–2, the student starts running towards the bus with a uniform velocity u. Assuming the motion to be along a straight road, the minimum value of u, so that the student is able to catch the bus is
A ship A is moving Westwards with a speed of 10 km h¯¹and a ship B 100 km South of A, is moving Northwards with a speed of 10 km h¯¹. The time after which the distance between them becomes shortest, is:
The speed of a swimmer in still water is 20 m/s. The speed of river water is 10 m /s and due east. If he is standing on the south bank and wishes to cross the river along the shortest path the angle at which he should make his stroke w.r.t. north is given by :-
A person standing on the floor of an elevator drops a coin. The coin reaches the floor in time t1 if the elevator is moving uniformly. Then depending upon whether the lift is going up or dow
A passenger train of length 60 m travels at a speed of 80 km/hr. Another freight train of length 120 m travels at a speed of 30 km/hr. the ratio of times taken by the passenger train to completely cross the freight train when : (i) they are moving in the same direction and (ii) in the opposite directions is :
A runner completes one round of a circular path of radius r in 40 seconds. His displacement after 2 minutes 20 seconds will be
A person moves 30 m north and then 20 m towards east and finally 30√2m in south-west direction. The displacement of the person from the origin will be
A hall has the dimensions 10 m × 10 m × 10 m. A fly starting at one corner ends up at a diagonally opposite corner. The magnitude of its displacement is nearly
A particle starting from the origin (0, 0) moves in a straight line in the (x, y) plane. Its coordinates at a later time are (√3, 3). The path of the particle makes with the x-axis an angle of :
A car travels a distance of 2000m. If the first half distance is covered at 40 km/hour and the second half at velocity v and if the average velocity is 48 km/hour then the value of v is
A particle moves towards east for 2 sec with velocity 15 m/s and move towards north for 8 sec with velocity 5 m/s. Then average velocity of the particle is :
Which of the following is a one dimensional motion
The ratio of the numerical values of the average velocity and average speed of a body is always
