unit 8 worked more answers - animated science · 9) a stone is thrown horizontally with a velocity...

Mr Powell 2009 Index

Unit 8 Worked More Answers...

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Problem Sheet 8.5


Problem Sheet 1


1) a 0.018s b) 0.036s 2) a) 10m/s2 bi) 45m bii) 3s c) 15s d) 18s) e) 371.8m f) 123.2m 3) a) 9.53m/s b) 10.27 m/s 4) 60m

Problem Sheet 1


3 18

Time in s

Velocity in m/s

30

2) (problem sheet 1)

450

45

Antelope & Cheetah


2.2 18

Time in s

Velocity in m/s

22

2) cont…. (problem sheet 1)

Answer fits here to fill in the unknown!

Now work out the total area under graph for distance travelled = 371.8

347.6

24.2

Antelope & Cheetah


1.5 10.49 Time in s

Velocity in m/s

v

3) Is solved using simultaneous equations (problem sheet 1)

S1

S2

In a 100m race we know total s = s1+s2

1) Set up two equations one for each part of journey 2) Add together and should = 100m 3) As final “V” is the same for both sub into equation

for s 4) Velocity v is found

Antelope & Cheetah

Problem Sheet 8.8

Use the simulation to help you….

http://www.walter-fendt.de/ph11e/projectile.htm

Questions 1-3 simply use the

4th Law of Uniformly Accelerated Motion

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Questions 4-9 combine the 1st and 3rd

Laws of Uniformly Accelerated Motion

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NB: We should also be aware that gravitational attraction produces a force which, on earth, causes a free-fall acceleration g of approximately 9.8 m/s2. Free vertical motion (or freefall) is simply uniformly accelerated motion in which a = g = +/- 9.8 m/s2, depending on the direction chosen as positive. (This assumes there are no resistive forces like air or water resistance).

5) A cricket ball is thrown vertically upwards with a velocity of 20 m/s. Calculate a) the maximum height reached. b) the time taken to return to earth.

a)

b)

6) A ball is dropped from a cliff top and takes 3.0 s to reach the beach below. Calculate a) the height of the cliff b) the velocity acquired by the ball.

a) b)

S = 44.1m

7) With what velocity must a ball be thrown upwards to reach a height of 15m?

8) A man stands on the edge of a cliff and throws a stone vertically upwards at 15 m/s. After what time will the stone hit the ground 20m below?

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33.3

81.9

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9) A stone is thrown horizontally with a velocity of 3.0 m/s from the top of a vertical cliff 200m high. There are no horizontal forces acting on the stone (therefore acceleration in the horizontal direction is zero). The only vertical force is that of gravity. Calculate;

a) how long it takes to reach the ground. b) its distance from the foot of the cliff. c) its vertical and horizontal components of velocity when it hits the ground.


Thrust SSC Answers

1 (a) (i) Uniform acceleration (ii) Non-uniform acceleration After 4 s, acceleration first increases (slightly) then decreases. (NB NO deceleration, acceleration does NOT become negative) (b) a = dv/dt = 180 m s-1/10 s (or similar values read from tangent to graph on next slide) = 18.0 m s-1

(c) 100 small squares represent 1000 m area under graph is about 62 small squares so displacement is about 1000 m x 62/100 = 620 m (or similar value deduced from area of graph)


Thrust SSC Answers

Exam Book Questions...


Exam Question ...June 02 Spec A Q1

1) The graph below shows how the velocity of a toy train moving in a straight line varies over a period of time. Describe the motion of the train in the following regions of the graph.

AB BC CD DE EF (5 marks)


Exam Question ...June 02 Spec A Q1

1) The graph below shows how the velocity of a toy train moving in a straight line varies over a period of time.

(b) What feature of the graph represents the displacement of the train? (1 mark) (c) Explain, with reference to the graph, why the distance travelled by the train is different from its displacement (2 marks


Exam Question ...Jan 07 Spec A Q2

2 (a) A cheetah accelerating uniformly from rest reaches a speed of 29ms-1 in 2.0 s and then maintains this speed for 15 s. Calculate (i) its acceleration, (ii) the distance it travels while accelerating, (iii) the distance it travels while it is moving at constant speed. (4 marks)



(b) The cheetah and an antelope are both at rest and 100 m apart. The cheetah starts to chase the antelope. The antelope takes 0.50 s to react. It then accelerates uniformly for 2.0 s to a speed of 25ms-1 and then maintains this speed. The graph shows the speed time graph for the cheetah. (i) Using the same axes plot the speed-time graph for the antelope during the chase.



2 (a) A cheetah accelerating uniformly from rest reaches a speed of 29ms.1 in 2.0 s and then maintains this speed for 15 s. Calculate (i) its acceleration, (ii) the distance it travels while accelerating, (iii) the distance it travels while it is moving at constant speed. (4 marks)



(b) The cheetah and an antelope are both at rest and 100 m apart. The cheetah starts to chase the antelope. The antelope takes 0.50 s to react. It then accelerates uniformly for 2.0 s to a speed of 25ms.1 and then maintains this speed. The graph shows the speed time graph for the cheetah. (ii) Calculate the distance covered by the antelope in the 17 s after the cheetah started to run. (iii) How far apart are the cheetah and the antelope after 17 s?

unit 8 worked more answers - animated science · 9) a stone is thrown horizontally with a velocity...

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