2.
When an object moves in a circular path at aconstant speed, a resultant force is
Addu High School DEPARTMENT OF SCIENCE AND TECHNOLOGY required.
Hithadhoo/Addu PHYSICS (a) State why a resultant force is required and the direction of this force
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TOPIC: circular motion Worksheet …………………………………………………………………………………………………………
(b) When an aeroplane is flying there is an upward force called lift which acts at
1. A plane is flying at constant velocity,
right angles to the wings. When the aeroplane is flying in a straighjt line,the lift
as shown.
force is equal to the weight of the
The pilot banks the plane an the lift force L is
aeroplane
now inclined at an angle ө to the vertical.
The diagram shows an aeroplanethat is
moving in a horizontal circleat constant
(a) Explain why this result in circular motion
speed.
(i)Explain in terms of forces, why the aeroplane is
…………………………………………………………………………………………………… able to fly in a circular path
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(b) Th plane continues to fly with a constant speed v. ……………………………………………………………………………………………………………
Th angle ө is given by tanө =v2 / rg …………………………………………………………………………………………………………...
Where r is the radius of the circular path (ii) The aeroplane has a mass of 2.4 x 106 kg and is flying in a horizontal circle at a
(i) Show that this equation is correct. constant speed of 85 m/s when ө is 250.
By considering both the horizontal and vertical motion, calculate the radius of the
circular path of th e aeroplane.
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(ii)
Calculaet the radius of the circular path. 3. The photograph shows part of the cycling track used in
v= 150 m/s the London 2012 Olympic Games. On the bend the
ө= 100 track is banked so that the outside of the track is higher
………………………………………………………………………………………………………… than the inside of the track.
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Addu high school/Dept of Science/Physics/unit 4/work sheet /circular motion 1
The diagram shows the forces R and W acting on a
cyclist travelling at a constant speed around the bend.
(a) Explain why there must be a resultant force acting
on the cyclist. (2)
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(b) Explain why a banked track is an advantage to cyclists. (2) 5. A track for go-karts is being built in a park.
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The design criteria state that the track
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must have semicircular ends with straight
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track in between, as shown.
(c) An inflatable airbag helmet for cyclists has been designed to prevent head
injuries.It is worn like a scarf around the neck. The track must allow the go-kart to travel safely at speeds up to 35.0 km per hour
In-built sensors detect when the cyclist
is involved in a crash and inflate the airbag (9.72 m s–1) on the bends. mass of go-kart
over the cyclist’s head in 0.1 s.
and driver = 185 kg diameter AB of
The graph shows how the force on a cyclist’s semicircular end = 30.0 m
head during a collision varies with time
(a) For one design the track is horizontal. As
when an airbag is not used.
the go-kart goes round the semicircular
Add to the axes, the graph that shows how the force on a cyclist’s head during a collision
varies with time when the airbag is used. end of the track, centripetal force is
Justify the shape of your provided by friction between the track and the tyres. This is shown in the free
graph.
(3) body force diagram below.
Show that this design meets the design criteria.
Addu high school/Dept of Science/Physics/unit 4/work sheet /circular motion 2
maximum frictional force = 1180 N (2) (c) A banked track will cost more to build. Suggest whether there are any
………………………………………………………………………………………………………… significant advantages that would justify the cost. (2)
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(b) A second design uses a track that is …………………………………………………………………………………………………………
banked at the semicircular ends. The 6. A DVD is rotating at 570 rotations per minute. What is its angular velocity
track is banked at an angle ș to the in radians per second?
horizontal. A. 1.5 B. 10 C. 60
At a particular speed v, the go-kart can D. 3600
follow the track without any frictional 7. The London Eye consists of a large vertical circle
with 32 equally-spaced constant speed of 0.26 m s–1
force perpendicular to its motion. The diagram shows the forces on the go-kart as and moves around a circle of radius 61 m.
it is moving away. (a)Calculate the time taken for each cabin to make one
complete revolution.(2)
(b) Calculate the centripetal force acting on each cabin. (mass of cabin = 9.7 × 10 3
kg) (2)
where d is the diameter AB of the curved part of the track. (3) ……………………………………………………………………………………
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(ii) Calculate the angle ș using the stated design criteria for this track. (2) …………………………………………………
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………………………………………………………………………………………………………… (a) The diagram shows just the circle and the
cabins. Draw arrows to show the direction of
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the centripetal force acting on a person in a cabin when the person is at each
……… of positions A, B and C.
(ii) As the person in a cabin moves around the circle, the normal contact force
between the person and the cabin varies.
Addu high school/Dept of Science/Physics/unit 4/work sheet /circular motion 3
State the position at which this force will be a maximum and the position at
which it will be a minimum. Explain your answers.
Addu high school/Dept of Science/Physics/unit 4/work sheet /circular motion 4
