- The moment is the turning effect of the force and can be increased by increasing the length of the instrument being used or the amount of force being used.
- moment = force x perpendicular distance from pivot
- The force exerted is known as the effort, the object is called the load, and the pivot the turning point.
- The centre of mass or the centre of gravity is an imaginary point within an object where we say the weight is acting.
- An object is in equilibrium when the centre of mass lies directly under the point of suspension.
- The turning effect causes an object in non-equilibrium to move back into equilibrium.
- The pivot doesn’t have to be in the centre of an object for a moment to be in balance.
- sum of all clockwise moments about a point = sum of all anti-clockwise moments
- W1 x D1 = W2 x D2
- All objects have a certain stability.
- When the weight’s line of action is outside the base of the object it topples over.
- When an object is moving in a circular direction at a constant speed at any moment its velocity is continuously changing direction as it moves around in the circle and the velocity is directed to the circle of direction along a tangent.
- The force being placed on the object acts towards the centre of the circle as is called the centripetal force.
- All object exert a gravitational force on each other.
- Gravity is a force of attraction, increases as the mass of the objects increases and decreases as the distance between the objects increases.
- Objects orbit objects larger than themselves.
- There’s a centripetal force present due to the gravitational forces of attraction between the larger object and the smaller ones.
- The planets further from the Sun travel at a slower speed because the gravitational force is weaker.
- Like planets, the further away a satellite is to Earth, the slower it travels.
- Satellites need to be travelling at the right speed in order to start orbiting the Earth.