The rear side of a truck is open and a box of 50 kg mass is placed 5 m away from the rear end.The coefficient of friction between the box and the surface below it is 0.15.On a straight road the truck starts from rest and accelerates at 2 m/s2 .At what distance from the starting point does the box fall off the truck ?(g = 10 m/s2 )
10 m
5 m
25 m
20 m
To avoid slipping while walking on ice one should take smallest steps because of the
larger friction
larger normal reaction
smaller friction
smaller normal reaction
Which of the following is not an example of perfectly inelastic collision ?
A bullet fired into a block if bullet gets embedded into block
Capture of electrons by an atom
A man jumping on to a moving boat
A ball bearing striking another ball bearing
If the force on a rocket moving with a velocity of 300 m/s is 345 N, then the rate of combustion of the fuel ,is
0.55 kg/s
0.75 kg/s
1.15 kg/s
2.25 kg/s
When a bullet of mass 5 kg is fired, the impulse on it is 200 Ns. If the mass of the gun is 10 kg, then the recoil velocity of the gun is
20 ms-1
2 ms-1
0.2 ms-1
0.02 ms-1
A balloon contains 10 g of air. The air begins to escape from a small hole in the balloon at the rate of 4 cms-1 and it completely shrinks in 2 seconds. What is the average force on the balloon?
5 dyne
10 dyne
15 dyne
20 dyne
A block of 10 kg is pulled at a constant speed on a rough horizontal surface by a force of 20 N.Find the co- effecient of kinetic friction .Given that g = 10 m/s2 .
0.2
0.5
0.85
0.7
A passenger in the bus finds that his suit case suddenly starts sliding backwards. This means that the bus is
turning left
turning right
accelerating
retarding
The upper half of an inclined plane of inclination θ is perfectly smooth while the lower is rough.A body starting from rest at the top comes back to rest at the bottom,if the coeffecient of friction for the lower half is given by
μ = sin θ
μ = cotθ
μ = 2 cosθ
μ = 2 tanθ
A 600 kg rocket is set for a vertical firing.If the exhaust speed is 1000 m/s,the mass of the gas ejected per second to supply the thrust needed to overcome the weight of rocket is
117.6 kgs-1
58.6 kgs-1
6 kgs-1
76.4 kgs-1
