Motion
What is the difference between distance and displacement?
Distance is the total path length traveled, while displacement is the straight-line distance between the start and end points, with direction.
What are Newton's 3 laws of motion?
1st law: An object at rest stays at rest, and an object in motion stays in motion at constant velocity unless acted upon by an external force.
2nd law: The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass (F=ma).
3rd law: For every action, there is an equal and opposite reaction.
Define work in terms of physics
Work is done when a force causes an object to move in the direction of the force (W=F⋅d).
What is the relationship between force and distance in doing work with a machine?
Increasing the distance can allow the same amount of work to be done with less force.
How is momentum calculated?
Momentum is the product of an object's mass and velocity (p=mv).
How do you calculate average velocity?
Average velocity is calculated as distance divided by time.
How does friction affect motion?
Friction opposes motion, slowing objects down.
How is power defined and calculated?
Power is the rate of doing work, calculated as P=W/t.
Explain the mechanical advantage of a machine.
What are the two kinds?
Mechanical advantage is the factor by which a machine multiplies the input force.
Ideal and actual mechanical advantage.
How does gravitational potential energy change with height?
It increases as height increases, calculated by PE=mgh.
How is acceleration calculated?
Acceleration is the change in velocity divided by the time taken for that change (a=Δv/Δt).
Explain how mass and weight differ.
Mass is the amount of matter in an object, constant everywhere, while weight is the gravitational force on the object, varying with gravity.
What is the relationship between work and energy?
Work is a transfer of energy.
Describe how a lever works.
A lever amplifies input force by increasing the distance over which the force is applied, pivoting around a fulcrum.
Describe the transfer of energy in a pendulum.
Energy transforms between kinetic and potential energy as the pendulum swings, with total mechanical energy conserved.
What is the effect of an object’s mass on its acceleration if the same force is applied?
Greater mass results in lower acceleration (a=F/ma=F/m).
Lower mass results in higher acceleration (a=F/ma=F/m).
1. Define net force.
2. What is the effect of unbalanced forces on an object?
1. Net force is the vector sum of all forces acting on an object.
2. It causes the object to accelerate in the direction of the net force.
What is the difference between potential and kinetic energy?
Potential energy is stored energy due to position, while kinetic energy is energy due to motion.
How do pulleys make lifting easier?
Pulleys change the direction of the force and can also multiply force when used in a system.
A 1500 kg car is traveling at a speed of 20 m/s. Calculate its kinetic energy.
The kinetic energy of the car is 300,000 Joules.
What is the significance of zero acceleration?
It means the object is moving at a constant velocity OR is at rest.
A car of mass 1200 kg is moving with a constant velocity. If the frictional force opposing the motion is 400 N, what is the applied force?
The applied force is 400 N.
What happens to power output if the same amount of work is done in half the time?
Power output doubles because power is the rate of doing work (P=W/t), and reducing time increases the rate.
What is the efficiency of a machine?
Efficiency is the ratio of useful work output to total work input, expressed as a percentage.
A 2 kg object is lifted to a height where its potential energy is 196 Joules. Calculate the height to which it was lifted.
The object was lifted to a height of 10 meters.