forces and motion

• what is the difference between speed and velocity?


  Speed is a scalar quantity that measures how fast an object is moving, while velocity is a vector quantity that measures both the speed and direction of an object's motion.
• what does scalar mean?


  a quantity that only has magnitude
• what does vector mean?


  a quantity that has both a magnitude and a direction
• what is the difference between distance and displacement?


  Distance is a scalar quantity as it only has a magnitude.

  Displacement is a vector quantity as it has both a magnitude and a direction.

  Displacement is the shortest distance between the start and end points.
• what is the formula for displacement?


  displacement = final position - initial position
• what is the formula formula for velocity?


  velocity = displacement / time
• what is the speed of sound in air?


  330m/s
• what is the approximate speed of a car?


  25m/s
• what is the approximate speed of an aeroplane?


  250m/s
• describe what acceleration means


  acceleration is the rate of change in velocity
• what is the word for negative acceleration?


  deceleration
• in terms of velocity, what do the letters u and v mean?


  u is initial velocity

  v is final velocity
• what is the formula that links acceleration, velocity and time?


  acceleration = change in velocity / time
• what is the formula that links acceleration, initial velocity, final velocity and displacement?


  2as=v^2 - u^2
• what does a distance-time graph show?


  how the distance travelled by an object changes over time
• what is on the x-axis and y-axis of a distance-time graph?


  distance is on the y-axis

  time is on the x-axis
• how do you find the seed of an object from a distance-time graph?


  find the gradient of the line at a particular point
• is electromagnetism a contact or non-contact force?


  electromagnetism is a non-contact force.
• why does an object in circular motion accelerate?


  an object in circular motion is constantly accelerating because the velocity is changing contiously
• what is the formula for momentum?


  momentum (kg m/s) = mass (kg) x velocity (m/s)
• what is a resultant force?


  the resultant force is the overall force acting on an object, taking into account all the different forces acting on it.
• which factor affects both thinking distance and braking distance?


  the speed of the vehicle
• what is gravitational potential energy?


  an object's gravitational potential energy is the energy it has due to its height in a gravitational field.
• how many digits should you use when writing bearings?


  always use 3 digits - e.g. 067°, not 67°.
• what is the conservation of momentum principle?


  total momentum before collision = total momentum after collision
• what is stopping distance?


  stopping distance is the total distance a car travels from the moment when the driver first notices an obstruction, to when the car stops.
• is tension a contact or non-contact force?


  tension is a contact force
• if a vehicle drives twice as fast, what happens to the breaking distance?


  the braking distance will increase by four times
• which forces act on an aeroplane?

  lift, thrust, weight, air resistance/drag
• what is braking distance?


  braking distance is the distance a car travels between the point a driver applies the brakes and the point the car stops moving.
• is friction a contact or non-contact force?


  friction is a contact force
• what happens to velocity of an object in circular motion?


  the velocity continuously changes due to a continuously changing direction
• what is the newton's first law?

  a resultant force is required to change the motion of an object
• is electromagnetism a contact or non-contact force?


  electromagnetism is a non-contact force
• does a driver's reaction time affect their thinking distance, braking distance or both?


  only their thinking distance
• what is the formula for weight?


  weight = mass x gravitational strength
• what does the length and direction of each arrow on a free body diagram indicate?


  the length of each arrow indicates the magnitude of that force

  the direction of each arrow indicates the direction of the force
• how do air bags work?


  air bags provide a soft surface to collide with during a car crash.

  by being flexible, they increase the time taken for the body's momentum to reach zero, and so reduce the forces acting on the body.
• what is gravity?


  gravity is an invisible force that pulls objects towards each other.
• what is newton's third law?

  whenever two object interact, they exert equal and opposite forces on each other.