A 50-kg object is accelerating to the right at 10 m/s2. What is the magnitude of the rightward net force acting on it (in Newtons) - 500kgm/s2 (f=ma)
Force could be a - push or a pull.
A force arises due to- the interaction between two objects.
Force has magnitude as well as direction.
A change in the speed of an object or the direction of its motion or both implies - a changein its state of motion.
Force acting on an object may cause a change in its state of motion or a change in its shape.
Force per unit area is called -pressure.
Liquids and gases exert pressure on - the walls of their containers.
The pressure exerted by air around us is known as - atmosphericpressure.
Friction opposes the relative motion between - two surfaces incontact. It acts on - both thesurfaces.
Friction depends on the nature of - the surfaces in contact.
Static friction comes into play when we try to move - an object atrest.
Sliding friction comes into play when an object is - sliding over oneanother.
Sliding friction is smaller than - static friction (static friction >kinetic friction > rolling friction)
Friction is important for - many of our activities. (without friction we
can't walk)
Friction can be increased by - making a surface rough.
The sole of the shoes and the tyres of the vehicles are - treading toincrease friction.
Friction is something - undesirable.
Friction can be reduced by - using lubricants, polishing, proper selection of material.
When one body rolls over another body, rolling friction is - smaller thansliding friction.
In many machines, friction is reduced by - using ball bearings.
Fluid friction can be minimised by giving - suitable shapes to bodiesmoving in fluids.
24. the force applied to a cable or wire that is anchored on opposite ends to opposing walls or other objects. This causes a force that pulls equally in both directions - Tensionforce
The spring force is the force created by a - compressed or stretched spring.
26. An object travels equal distances in equal intervals of time, then it is said to be – uniform
27. if velocity decreases with time, then its acceleration is negative called - deceleration or retardation.
28. Acceleration is a - vector quantity and its SI unit is - ms-2
29. Graphical representation of motion, Displacement and time graph- Uniform velocity (straightline)
If anybody is falling freely under gravity, then acceleration is - Positive acceleration due togravitational force (g)
If an object is thrown vertically upward, then acceleration is – negative acceleration due togravitational force (-g)
For a body with zero acceleration or constant speed, graph between velocity and time will be - a straight line parallel to time axis.
For accelerating or decelerating body the graph will be a - straight lineinclined to time axis and velocityaxis
35. Graph between position (distance)-time for an accelerating or decelerating body is always - a
36. Acceleration-time graph for uniformly accelerating body is a - lineparallel to time axis.
37. In case of uniformly accelerated motion, the graph between - velocityand time is always a straight line.
The motion of a bullet shot from the gun, the motion of a rocket after burning out, the motion of a bomb dropped from an aero plane are - Projectile Motion.
39. If we drop a ball from a height and at the same time thrown another ball in a horizontal direction, then both the balls would - strike the earthsimultaneously at different places.
40. Circular motion with a constant speed is called - uniform circular motion.
41. During circular motion an acceleration acts on the body towards the centre, called - centripetal acceleration.
The direction of centripetal acceleration is always towards - thecentre of the circular path
SI unit force is - newton (N) and CGS unit is - dyne. (1 N = 10−5 dyne.)
44. During circular motion a force always acts on the body towards the centre of the circular path, called - centripetal force. (centripetalforce = m?2?)
45. In circular motion we experience that a force is acting on us in opposite to the direction of centripetal force called – centrifugal
centrifugal force is an - apparent force or imaginary force and called a pseudo force.
Cyclist inclined itself from vertical to obtain required - centripetal force
For taking turn on a curved road, the frictional forces acting between the tyre of the vehicle and the road acts as - centripetal force.
48. If a bucket containing water is revolved fast in a vertical plane, the water may not fall even when bucket is completely inverted because -centrifugal force
49. For orbital motion of electrons around the nucleus electrostatic force of attraction is acting between the electrons and the nucleus as - centripetal force.
50. Cream is separated from milk when it is rotated in a vessel about the same axis - a centrifugal force
For revolution of the earth around the sun, gravitational force of attraction between the earth and the sun acts as - centripetal force.
52. A body continues in its state of rest or of uniform motion in a straight line unless an external force act on it. It is based on - law of inertiaor law of Galileo.
When a bus or train at rest starts, to move suddenly, the passengers sitting in it jerk in backward direction due to their - inertia of rest.
The dust particles come out from
a carpet when it is beaten with a stick due to their - inertia of rest.
A passenger jumping out from a rapidly moving bus or train is advised to jump in forward direction and run forward for a short mile due to - inertia of rest.
When a running bus or train stops suddenly, the passengers sitting in it jerk in forward direction due to - inertia of motion
In Projectile motion, Maximum range θ = 45° and maximum height θ=90°
SI unit of impulse - N-s (or) Kg m/s
59. Newton's second law of motion- Force =Mass x Acceleration (unit-N)
60. On firing the bullet, the gunner is pushed in backward direction because of - Newton's third law
A cricketer moves his hands backwards while catching a ball because of - Impulse
A person jumping from a height on a concrete floor receives more injury than when jumping on a spongy floor because of - Impulse
