Page 295 - General Knowledge

GENERAL KNOWLEDGE 2019

 It is because of its inertia that matter behaves according to this law.
 The idea that something would keep moving at a constant velocity for like forever is
something that we don‘t see happen very often on the earth, because when something is
moving, there is almost always an outside force acting on it. It is usually friction.
 This is why a ball rolling along a straight section of road will come to a stop all on its own.
 Friction slows it down and makes it stop.

 When the net external force acting on an object is zero, the acceleration of the object is zero
and it moves with a constant velocity.
 Of course, if it is at rest, it will remain at rest.
If ∑ Then a = 0 and v is constant
The Second Law
 The acceleration of an object as produced by a net force is directly proportional to the
magnitude of the net force, in the same direction as the net force, and inversely proportional
to the mass of the object.
 Force is a push or a pull. Acceleration is when the motion of an object changes.
 Mass is the amount of matter in an object.
2
 Acceleration (in meters / second ) = net force (in newton‘s) / mass (in kilograms.

 In this equation, ―a‖ is the acceleration, m is the mass, and is the net force.
 If both sides of the above equation are multiplied by the mass, the equation can be written
this way:

 Units of Force = Newton (N)
 SI units for mass is kg

 SI units for acceleration is

1 Newton (N) = 1kg
Gravity and Weight
 Gravity is the force of an attraction that exists between any two objects that have mass.
 The force of gravity depends on the mass of the objects and the distance between them.
 Weight is a force, like the push of your hand is a force, and is measured in Newton.
 The force of gravity causes all objects near Earth‘s surface to fall with an acceleration of 9.8
2
m/s .
 Your weight on Earth is the gravitational force between you and the Earth.

Weight and mass
 Weight is a force, like the push of your hand is a force, and is measured in newton.
 Mass is the amount of matter in an object, and doesn‘t depend on location.
 Weight will vary with location, but mass will remain constant.

Circular motion
 Circular motion is the movement of an object along the circumference of a circle or rotation
along a circular path.
 It can be uniform, with a constant angular rate of rotation and constant speed, or non-
uniform with a changing rate of rotation.

291 | P a g e shop.ssbcrack.com