I'm am currently studying Engineering Physics by distance education
and I have done a past exam paper and am trying to get the correct
answers and working so as I can compare them to mine. Obviously this isn't the
exam we will be doing and it can only be of benefit to me in terms of
knowing where and if I have gone wrong.
Question 1
A car travelling at 100 kmh-1 decelerates uniformly at 1.8 ms-2.
Calculate:
a.the distance it goes before it stops;
b.the time it takes to stop; and
c.the distance it travels during the first and third seconds.
Question 2
A man pushes a 16 kg lawn mower at a constant speed with a force F =
90 N directed along the handle, which is at an angle of 45° to the
horizontal (see below). Calculate:
a.the horizontal retarding force on the mower;
b.the normal force exerted vertically upward on the mower by the
ground; and
c.the force the man must exert on the lawn mower to accelerate it from
rest to 1.5 ms-1 in 2.5 seconds. Assume the same retarding force.
Question 3
The skier in the figure below has just begun descending the 30° slope.
Assuming the coefficient of kinetic friction is 0.10, calculate:
a.Her acceleration.
b.The speed she will reach after 6.0 s.
Question 4
At the instant a race began, a 55 kg sprinter was found to exert a
force of 800 N, at a 25° angle with respect to the ground, on the
starting block.
a.What was the horizontal acceleration of the sprinter?
b.If the force was exerted for 0.38 seconds, with what horizontal
speed did the sprinter leave the starting block?
Question 5
Two boxes connected by a lightweight cord are resting on a table. The
boxes have masses of 12 kg and 10 kg. A horizontal force FP of 40 N is
applied by a person to the 10 kg box as shown in the figure. Find:
a.the acceleration of each box; and
b.the tension in the cord.
Question 6
A 0.300 kg ball, moving with a speed of 2.50 ms-1, has a head-on
collision with a 0.600 kg ball initially moving away from it at a
speed of 1.00 ms-1. Assuming a perfectly elastic collision, what is
the speed and direction of each ball after the collision?
Question 7
1.i. If the KE of a particle is doubled, by what factor has its speed
increased?
ii.If the speed of a particle is doubled, by what factor does its KE
increase?
2.i. How much work must be done to stop a 1000 kg car travelling at
100 km/h?
ii.If the car stops in a distance of 193 m, determine the average
force which stopped the car.
Question 8
A marble column of cross-sectional area 1.5 m2 supports a mass of
30,000 kg.
a.What is the stress within the column?
b.What is the strain?
c.By how much is the column shortened if it is 10.5 m high?
Take the Young's Modulus for marble as 50 ´ 109 Nm-2.
Question 9
Two parallel and opposite forces, each of 4000 N, are applied
tangentially to the upper and lower faces of a cubical steel block 25
cm on a side. Calculate:
a.the angle of shear; and
b.the displacement of the upper surface relative to the lower surface.
Take the shear modulus of steel as 8 ´ 1010 Nm-2.
Question 10
a.The gauge pressure in a hydraulic lift is 16 atm. What is the mass
of the heaviest vehicle it can lift if the diameter of the output line
is 17 cm?
(1 atm = 1.01 ´ 105 Nm-2)
b.A 0.40 kg piece of wood floats in water but is found to sink in
alcohol, in which it has an apparent mass of 0.020 kg. What is the
density of wood?
The density of alcohol is 0.79 ´ 103 kg m-3. |
