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Mechanics Questions
Newton's Laws of Motion
Question 1
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During take-off, an
aircraft accelerates
at 3·4ms-2.
The total mass of
the aircraft is
8×103kg. |
| Calculate |
| a) |
the
net force acting on
the aircraft during
the acceleration |
| b) |
the
speed of the
aircraft after 5
seconds of
acceleration. |
Question 2
| A person on a bicycle is moving at 15ms-1 on a horizontal road. The total mass of the person plus the bicycle is 90kg. The person stops pedalling and comes to rest in 12s. Calculate the average magnitude of the force causing the bicycle to slow down. |
Question 3
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A mass m = 2·5kg
is being accelerated
upwards by the
tension in a string,
as shown below. |
 |
|
The magnitude of the
acceleration a =
4ms-2.
If the acceleration
due to gravity is g
= 10ms-2,
calculate the
magnitude of the
tension in the
string. |
Question 4
| A person stands in an elevator. The person has a mass of 60kg. Calculate the apparent weight of the person when the elevator is accelerating downwards at 2·5ms-2. |
Question 5
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A block of wood of
mass m = 250g is being pulled along a surface by a force F = 20N.
The force of
friction between the
block and the
surface has a
magnitude of 15N,
see diagram below. |
 |
|
a) |
the acceleration of
the block |
|
b) |
the distance moved,
starting from rest,
in
5s. |
Question 6
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The diagram below shows two masses hanging on
a string passing over a light, frictionless
pulley. |
|
 |
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a) |
Calculate the acceleration of the masses,
given that m1 =
3kg
and m2 = 1.5kg. |
|
b) |
Calculate the magnitude of the tension in the
string when the masses are accelerating. |
Question 7
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In the diagram below, the object placed on
the right hand scale pan has a mass M = 250g
and it causes both scale pans to accelerate
at 2.45ms-2. The
scale pans themselves each have a mass m. |
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 |
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a) |
Draw a diagram showing the forces which are
acting on the mass M. |
|
b) |
Find the force which the mass M exerts on
the scale pan. |
|
c) |
Assuming that the pulley moves without
friction and has negligible mass, calculate
the total mass of the two scale pans. |
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© David Hoult 2008 |
The Open Door Web Site