Which of the following statements about liquid pressure is NOT correct? The pressure
at a point in a liquid is proportional to the depth
at any point in a liquid is the same at the same level
is exerted equally in all directions at any point
of a liquid at any point on the wall of its container acts in a direction perpendicular to the wall
at a particular depth depends on the shape of the vessel
Correct answer is E
No explanation has been provided for this answer.
380g
400g
360g
39g
180g
Correct answer is A
R.d = 19, therefore, density = 19gcm-3
mass = velocity x density
= 20 x 19
= 380g
1.5 x 108m-1
2.0 x 108m-1
3.0 x 108m-1
4.5 x 108m-1
9.0 x 108m-1
Correct answer is B
n = \(\frac{\text{speed in air}}{\text{speed in glass}}\)
1.5 = \(\frac{3\times10^4}{\text{speed in glass}}\)
speed in glass = 2 x 108ms-1
The force with which an object is attracted to the earth is called its
acceleration
mass
gravity
impulse
weight
Correct answer is C
No explanation has been provided for this answer.
Which of the following statements about friction is NOT correct?
The force of kinetic friction is less than the force of static friction
The force of kinetic friction between two surfaces is independent of the areas in contact provided the normal reaction is unchanged
The force of rolling friction between two surfaces is less than the force of sliding friction
The angle of friction is the angle between the normal reaction and the force of friction
Friction may be reduced by lubrication
Correct answer is D
- Static Friction is friction which is experienced when an object is placed on a surface. And, Kinetic friction is due to the movement of an object on a surface.
- Static friction is greater than kinetic friction because there are more forces at work keeping an object stationary than there are forces working to resist an object once it is in motion.
- Rolling friction is the weakest type of friction, static being the strongest. The frictional force depends on the area of contact between the two bodies. As the area of contact is less in rolling friction than the sliding friction, so rolling friction is weaker than sliding friction.