A car of mass 1000 kg negotiates a banked curve of radius 90m on a frictionless road. If the banking angle is 45^{o}, the speed of the car is
20 ms^{-1}
30ms^{-1}
5 ms^{-1}
10 ms^{-1}
B.
30ms^{-1}
The angle of banking
Two sphere A and B of masses m_{1} and m_{2} respectively collide. A is at rest initially and B is moving with velocity v along the x -axis. After the collision, B has a velocity v/2 in a direction perpendicular to the original direction. The mass A moves after collision in the direction
same as that of B
opposite to that of B
C.
Here, P_{i} = m2vi +m_{2} x 0
The upper half of an inclined plane of the inclination is perfectly smooth while lower half is rough. A block starting from rest at the top of the plane will again come to rest at the bottom, if the coefficient of friction between the block and lower half of the plane is given by,
C.
An explosion breaks a rock into three parts in a horizontal plane. Two of them go off at right angles to each other. The first part of mass 1 kg moves with a speed of 12 m/s and the second part of mass 2 kg moves with second part of mass 2 kg moves with 8 m/s speed. If the third part flies off with 4 m/s speed, then its mass is,
3 kg
5 kg
7 kg
17 kg
B.
5 kg
We have,
p_{1} + p_{2} + p_{3} = 0 [ because p = mv]
Therefore,
1 x 12 i + 2 x 8 j + p_{3} = 0
Now. p_{3} = m_{3} v_{3}
This implies,