7 On the move

Question 1

What is displacement?

Answer 1

distance in a given direction

Question 2

what is speed?

Answer 2

the change of distance per unit time

Question 3

what is velocity?

Answer 3

the change of displacement per unit time (speed in a given direction)

Question 4

what is the formula for speed?

Answer 4

v = s/t

Question 5

what does a constant gradient mean in a distance time graph?

Answer 5

constant speed/velocity

Question 6

how do you find the gradient with a distance time graph of changing speed?

Answer 6

draw a tangent at any point and calculate the gradient from that

Question 7

what does constant velocity mean?

Answer 7

when an object moves at the same speed without changing direction

Question 8

what is acceleration?

Answer 8

the change of velocity per unit time

Question 9

what is uniform acceleration?

Answer 9

where the velocity of the object moving along a straight line changes at a constant rate

Question 10

what is the formula for acceleration?

Answer 10

a = (v - u)/t

Question 11

how can the formula for acceleration be rearranged?

Answer 11

v = u + at

Question 12

what does the gradient of a velocity time graph equal?

Answer 12

the acceleration

Question 13

what is equal to the displacement travelled on a velocity time graph?

Answer 13

the area under the graph

Question 14

what can be used when there is constant acceleration?

Answer 14

suvat equations

Question 15

what is acceleration of free fall?

Answer 15

acceleration of an object acted on only by the force of gravity

Question 16

what is a projectile?

Answer 16

any object acted upon only by the force of gravity

Question 17

what 3 principles apply to all projectiles?

Answer 17

1. the acceleration of an object is always equal to g and downwards as gravity acts downwards. the acceleration therefore only affects the vertical motion of the object
2. the horizontal velocity is always constant as the acceleration of the object doesn’t have a horizontal component
3. the motion in the horizontal and vertical directions are independent of each other

Question 18

what formula is used to work out horizontal displacement/velocity of a projectile?

Answer 18

s = vt

s - displacement
v - initial velocity
t - time

Question 19

what is used to calculate the vertical component of velocity (or variables relating to the vertical velocity)?

Answer 19

suvat equations

Question 20

what are the features of a drag force of a projectile?

Answer 20

• acts in opposite direction to direction of motion
• increases as speed increases
• has a horizontal component which reduces horizontal speed
• reduces maximum height of projectile if the initial direction is up

Question 21

what is used to find the vertical and horizontal components of an initial velocity of a projectile?

Answer 21

trig

vertical - U sin x
horizontal - U cos x

U - initial velocity
x - angle with horizontal