assessment 2 - physics

0 - 70 / 7 = 70 /7 = 10 m/s 2

A car advertisement states that a certain car can accelerate from rest to 70 km/h in 7 seconds. Find the car's average acceleration.

1st car: 8 / 3 = 2.67 m/s 2 2nd car: 30 / 8 = 3.75 m/s 2 no, the acceleration of the second car is higher

A cyclist accelerates from 0 m/s to 8 m/s in 3 seconds. What is his acceleration ? Is this acceleration higher than that of a car which accelerates from 0 to 30 m/s in 8 seconds?

15 / 2 = 7.5 m/s 2

A cyclist in the Tour de France accelerates down a hill from 22 m/s to a speed of 37 m/s. This acceleration takes him 2 seconds. Calculate the acceleration

58 m/s

A man skis down an 1160 m run in 20 seconds - how fast does he go?

14 / 2 = 7 m/s 2

Change in speed = 14 m/s; time taken = 2 seconds. Calculate the acceleration

^P = p x g x ^h

solve

465 m

How far can a cheetah run in 15 seconds at 31 m/s?

8100 m

How far could you cycle in 30 minutes, moving at 4.5 m/s?

1.05 m/s

How fast does a giant tortoise travel if they covered 45m in 43 s.

89 s

How long does a Tuna travelling at 18m/s take to go 16km?

50 x 3 = 150 150 + 10 = 160 (final velocity)

If a Ferrari, with an initial velocity of 10 m/s, accelerates at a rate of 50 m/s2 for 3 seconds, what will its final velocity be?

230 s

Raindrops fall at 9m/s. How long do they take to fall from a cloud 2070m from the ground?

the speed something is moving at a particular point in time

What is instantaneous speed?

change in y/change in x 10/10 1 m/s 2

calculate the acceleration in C

change in y / change in x 25/20 1.25 m/s 2

calculate the acceleration in D

person starts journey

describe what happens at point A

person is stationary

describe what happens at point B

person is stationary

describe what happens at point C

turns around

describe what happens at point D

arrives at location

describe what happens at point E

constant velocity (speed is not changing)

describe what is happening at line C

constant deceleration (speed is decreasing at a constant rate)

describe what is happening at line D

stationary

describe what is happening at line D

constant acceleration (speed is increasing at a constant rate)

describe what is happening at lines A and B

change in y/change in x (0,0) (3,15) 15/3 5 m/s

find the speed over 0-A

change in y/change in x (3,15) (8,15) 0/5 0 m/s

find the speed over AB

change in y/change in x (8,15) (12,0) 15/4 3.75 m/s

find the speed over BC

0-2 0-12 2/12 6

find the speed, if a line were to have a point at 0,0 and another at 2,12

rectangle: bh = 2 x 20 = 40 triangle: 1/2 bh = 1/2 5 x 20 = 50 40 + 50 = 90 m

find the stopping distance on this graph

you find the gradient gradient = change in y / change in x

how do you calculate speed from a distance x time graph?

you find the area of the line

how do you find distance on a speed x time graph

1. separate each line into a shape 2. find the area of each shape 3. add the areas up together

how would you calculate stopping distance on a graph

gradient = change in y/change in x 10/10 1 m/s 2

how would you find the acceleration of line B?

1. split into two shapes (triangle and rectangle) 2. find the area of each (1/2bh + bh) (1/2 10 x 10 + 10 x 15) (50 + 150) (200 m)

how would you find the distance moved at line B?

Na 2 or Pa

what are the units used for pressure?

change in

what does "^" mean in a formula

you are going towards the starting position

what does a downward slanted line on a distance x time graph mean?

its means the object is not moving, it is stationary

what does a straight line that is not on the x-axis mean on a distance x time graph?

you are going away from the starting position

what does an upward slanted line on a distance x time graph mean?

the average speed something is moving during the whole journey

what is average speed?

stopping distance = thinking distance + braking distance

what is stopping distance

the time between applying the breaks and stopping

what is the braking distance

speed is a scalar meaning it only has size, but velocity is a vector meaning it has both and direction

what is the difference between speed and velocity?

line A and line B are both accelerating, but line A is accelerating at a faster rate because it is steeper

what is the difference between what is happening at line A vs line B?

line A is going faster than line B because it steeper

what is the difference between what is happening at line A vs line B?

change in velocity (speed) / change in time final velocity-starting velocity / final speed-starting speed

what is the formula for acceleration

density = mass/volume

what is the formula for density?

distance = speed x time

what is the formula for distance?

change in y / change in x

what is the formula for finding acceleration on a speed x time graph

force ___________________________________ pressure x area

what is the formula for pressure when it is involving air or a solid?

^P (change in pressure) = p (density of fluid) x g (gravitational field strength) x ^H (change in height)

what is the formula for pressure when it is involving depth (water)?

speed = distance / time

what is the formula for speed?

time = distance / speed

what is the formula for time?

change in velocity = acceleration x time

what is the formula to find a change in velocity?

change in velocity = acceleration x time change in velocity + initial velocity = final velocity

what is the formula to find the final velocity when involving acceleration?

the time between seeing the hazard and applying the breaks

what is the thinking distance

m/s 2

what is the unit for acceleration

kg/m 2

what is the unit for density?

m

what is the unit for height?

m/s

what is the unit for speed

m/s

what units do we measure speed in?