1- Rectilinear motion

Question 1

Scalar/Vector quantities

Answer 1

• Scalar has magnitude but no direction
• e.g distance, speed, time
• Vector has both
• e.g velocity, displacement

Question 2

Velocity and acceleration

Answer 2

• Average velocity = total displacement over total time
• Instantaneous velocity = displacement over specific period of time over specific period of time
• Acceleration = change in velocity over change in time (final velocity - initial velocity/time)

Question 3

useful values

Answer 3

• speed of sound = 330 ms^-1
• speed of light = 3*10^8 ms^-1
• g = 9.81 Nkg^-1
• acceleration during freefall = -9.81 ms^-2

Question 4

Equations of motion (SUVAT)

Answer 4

• V = U+AT
• V^2 = U^2 + 2AS
• S = UT + 1/2AT^2
• S= VT - 1/2AT^2
• S = 1/2(U+V)T

Question 5

Free Falling

Answer 5

• all objects fall to earth at a rate of 9.81ms^-2 assuming there is no air resistance. if the object is travelling upwards, this also acts as the deceleration acting on it.
• objects travelling horizontally also fall at the exact same rate. Horizontal and Vertical components of motion act completely separately to each other, and can be found separately using the equations of motion.

Question 6

displacement time graphs

Answer 6

• gradient = velocity

- curved line means acceleration (increasing = upwards curve, vice versa)

Question 7

velocity time graphs

Answer 7

• gradient = acceleration
• flat line doesn’t mean there is no movement, just constant velocity
• total displacement = area under graph

Question 8

Acceleration/time graphs

Answer 8

• gradient = rate of change of acceleration
• flat line = constant acceleration
• total area under graph = change in velocity
• at constant velocity, graph immediately goes to 0

Question 9

Resolving vectors

Answer 9

• a vector at an angle can be resolved using trigonometry
• the adjacent to the angle is magnitude*cos(theta)
• the opposite to the angle is magnitude*sin(theta)