p2.1-Motion

Question 1

p2.1.1-How do you measure speed, distance, time?

Answer 1

You use a ruler to measure distance and stop clock to measure time. You can measure very short periods with a light beam. You can also ultrasound to measure the time taken for a pulse to travel there and back.

Question 2

p2.1.1-How do you calculate/convert units?

Answer 2

average speed = total distance / total time
1000m in km, 1609m in mile, 3600s in hour

Question 3

p2.1.2-What is the difference between a scalar and vector?

Answer 3

A scalar has a magnitude and no direction. A vector has a magnitude and direction. You represent vector with an arrow, length shows magnitude, direction of arrow shows direction.

Question 4

p2.1.2-What is the difference between distance and displacement?

Answer 4

Distance is the complete length between any two points in a path. Displacement is the direct length between the start and finish point. Distance is scalar, displacement is a vector.

Question 5

p2.1.2-What is the difference between speed and velocity?

Answer 5

Speed is the time rate at which an object is moving at. Velocity is the rate and direction of an objects movement. Speed is a scalar while velocity is a vector.

Question 6

p2.1.3-What is acceleration?

Answer 6

Acceleration is the rate of change of velocity. When an object moves in a circular path at a constant speed, it is still accelerating as the velocity is changing.

acceleration(m/s^2) = change in velocity(m/s) / time(s)
acceleration(m/s^2) = final velocity(m/s) - initial velocity(m/s) / time(s)

Question 7

p2.1.4-What does a graph of distance against time tell you?

Answer 7

It tells you the speed of an object on its journey. The speed is equal to the gradient of the graph. A straight line means the objects speed is constant as the gradient doesn’t change, a horizontal line means the object isn’t moving and a steeper line means the object is travelling faster.

Question 8

p2.1.4-How are distance and displacement time graphs different?

Answer 8

A distance time graph shows the total distance travelled. A displacement time graph shows the direction as well as the magnitude.

change in displacement = final displacement - initial displacement
velocity(m/s) = change in displacement(m) / time(s)

Question 9

p2.1.5-How do you calculate acceleration/displacement from graphs?

Answer 9

acceleration(m/s^2) = change in velocity(m/s) / time(s)
total displacement = split the graph into diff shapes, multiply velocity and time and add all together

Question 10

p2.1.6-What are velocity/kinetic energy calculations?

Answer 10

final velocity(m/s) - initial velocity(m/s) = 2 x acceleration(m/s^2) x distance(m)
kinetic energy(J) = 0.5 x mass(kg) x speed(m/s^2)
speed(m/s) = square root: kinetic energy(J) / 0.5 x mass(kg)