A1 Stuff You Didn't Do Well On

According to Newtons laws of motion which statement is false? a) A body at rest will remain at rest unless acted upon by an external force. b) If a body is acted upon by an external unbalanced force the body will have an acceleration in the direction and proportional to the magnitude of the force. c) For every action there is an equal and opposite reaction. d) A body in motion will come to rest unless acted upon by an external unbalanced force. e) When one object exerts a force on a second object the second object exerts a reactive force of equal magnitude and opposite direction on the first object.

D

Which of the following statements is false? a) kinetic friction is not affected by the body's speed b) kinetic friction is greater than rolling friction c) friction is affected by the relative roughness of the two surfaces d) kinetic friction is greater than static fiction e) force of friction is not affected by the area of the surfaces in contact

D

The coefficient of friction is defined as: a) the downward force on the two surfaces in contact b) the force parallel to the surface required to start an object moving c) the reaction normal perpendicular to the surface d) the force parallel to the surface required to keep an object moving at a constant linear velocity e) the ratio of the force required to move a body to the normal reaction force

E

Which of the following statements about simple machines is false? a) The machine receives energy by means of a single applied force. b) The machine produces work by means of a single output force. c) Work output is the product of the load and the distance moved by the load. d) Work input is greater than work output. e) The machine receives energy by means of 2 or more applied forces.

E

The unit of measure of energy used in the SI systems is

J

The SI unit for weight is

Newton

Moments are measured in:

Nm

010100020021000E If a system is in equilibrium then which of the following statements is true? a) The system will rotate clockwise b) The system will rotate counter clockwise c) The system will not rotate because no force is being exerted d) The system rotates under the largest force e) The system will not rotate because the moments in the system balance each other out

Won't move cause they're in equilibrium

A plane is flying at 600 km/h and reduces its velocity uniformly to 70 km/h in 3 minutes. What is its acceleration?

a) -0.818 m/s^2

Find the coefficient of friction between a 73 kg cubic box measuring 3 m and a hardwood floor 16 m long and 20 m wide if a total of 236 N is required to start the box moving.

a) 0.33

A small hand pump is 850 mm in length. The fulcrum is attached in one end and the load plunger is located 50 mm from the fulcrum. An effort force of 600 N is applied downward from the opposite end of the fulcrum. Find the force exerted by the load plunger and the mechanical advantage of the lever.

a) 10,200 N and 17

Public swimming pools require 3 parts chlorine liquid and 2 parts salt water to every 100 parts water to kill bacteria. How much chlorine liquid is required in a 4,000 L pool?

a) 114.29 L

A piston having an area of .2 m sq is subject to a pressure of 600 kPa. What is the total force exerted on the piston?

a) 120 kN

A mass of 600 kg is moved a horizontal distance of 40 m due to a force of 400 N. The amount of work done is

a) 16,000 J

A pump raises 650 tonnes of sea water a height of 55 m in 6 hours. If the pump efficiency is 100% what is the power required to drive the pump?

a) 16.24 kW

A lever is 3 m in length and is pivoted at one end. A load of 8,000 N is suspended from the lever at a point 1 m from the pivot. What force is necessary at the other end of the lever in order to obtain equilibrium?

a) 2,666.667 N

A wheel and axle has a mechanical advantage of 10. Calculate the diameter of the axle if the diameter of the wheel is 30 cm.

a) 3 cm

Find the magnitude and direction of the resultant of 3 coplanar forces of: i) 40 N 45 degrees east of south ii) 10 N west iii) 70 N 35 degrees east of north

a) 65 N 65 degrees east of north

The unit of acceleration in the SI system is

a) m/s^2

The rate of change of velocity is:

acceleration

The ratio of the load to the effort is called:

actual mechanical advantage

When two straight lines meet or cross each other, they form __________.

angle

A car travelling at 90 km/h is brought to rest over a distance of 120 m. What is the acceleration in metres per second squared?

b) -2.6

A force of 320 kN acts at a perpendicular distance of 4 m from a point. What will be the turning moment produced?

b) 1,280 kNm

Determine the resultant of the following vector system: i) 65 km 60 degrees south of east ii) 120 km 30 degrees west of north iii) 30 km 35 degrees east of north iv) 75 km south

b) 11 km 75 degrees west of south

Find the resultant of 3 concurrent coplanar forces of: i) 60 N acting 20 degrees east of north ii) 30 N east iii) 150 N acting 40 degrees east of south

b) 160 N 68 degrees east of south

A body moves from Point A to Point B in a semicircular path. The diameter of the semicircle is 2 m. Calculate the distance between Point A and Point B.

b) 3.14 m

A body moves from Point A to Point B in a semicircular path. The radius of the semicircle is 2 m. Calculate the displacement between Point A and Point B.

b) 4 m

A block and tackle system has 3 pulleys in each of two blocks. If a downward effort of 100 N is applied and the machine has an efficiency of 83.6% what is the maximum mass that can be moved?

b) 51.1 kg

Find the force necessary to just move a mass of 2.5 kg on the end of a 3.6 m lever which is pivoted 3 m from the left end.

b) 76.88 N

A cylinder with a diameter of 5 m and a height of 8 m is half full of liquid. What volume does the liquid occupy?

b) 78.5 cubic cm

A vehicle that travels 150 km in 3 hours,

b) has an average speed of 50 km/h

A scalar quantity has: a) necessary units only b) numerical size of the quantity only c) magnitude only d) both direction and numerical size of the quantity e) both magnitude and necessary units

both magnitude and necessary units

A car travelling at 18 km/h increases its velocity uniformly to 48 km/h in 6 seconds. What is the acceleration in metres per second squared?

c) 1.39

A machine is used to lift a load of 12 kN and the effort applied is 4 kN. What distance will the load move if the effort moved a distance of 8 m and the efficiency of the machine is 70%?

c) 1.8667 m

A 7 m bar is pivoted at 2 m from the left end. A force of 60 N is applied downward on the left end and a force of 20 N is applied downward on the right end. What would be the clockwise and counter-clockwise moments and in which direction would the bar rotate?

c) 120 Nm counter-clockwise, 100 Nm clockwise, counter-clockwise rotation

If the diameter of a cylinder is 1.5 m and the height is 223 cm, what is the surface area in square m? (Include the areas of the ends)

c) 14.043

A pump is required to raise 600 litres of fresh water a vertical distance of 120 m. If the efficiency of the pump is 45%, how much work must be done on the pump to raise the water?

c) 1570 kJ

A car has an initial speed of 35 km/h and in 75 seconds it accelerates to 120 km/h. What is the distance travelled during the acceleration period?

c) 1614 m

A vehicle travelling at 90 km/h decelerates uniformly to 50 km/h in 9 seconds. How far will the vehicle travel in this time?

c) 175 m

An airplane travels 250 km due West for 2 hours. Its average velocity is

c) 34.722 m/s West

010100020021000C Calculate the power required, to pump 50000 litres of water per minute to a vertical height of 72 m.

c) 588.6 kW

A body moves from A due east 5 m to B, then from B due north 6 m to C and finally from C due west 5 m to D. Calculate the total distance covered from A to D.

c) 6 m

An airplane travels 500 km due west in 2 hours. Its average velocity is

c) 69.4 m/s due west

A 15 m long bar is pivoted on the right end and a force of 5 N is applied downwards on the left end. The moment of force is

c) 75 Nm counter-clockwise

Which of the following is an example of a static body?

c) a rigid body that is at rest

A bar is pivoted on the left end and a force is applied downwards on the right end. The rotation of the bar will be

clockwise

A bar is pivoted on the right end and a force is applied upwards on the left end. The rotation of the bar will be

clockwise

Vectors that are all in the same plane are defined as:

coplanar

A bar is pivoted on the right end and a force is applied downwards on the left end. The rotation of the bar will be

counter clockwise

Which of the following statements is true if a person pushes with a force of 300 N on a rock and the rock does not move? a) 300 N of work was done b) 300 J of work was done c) 150 J of work was done d) no work was done

d

Solve the following equation for m, y = mt + c

d) (y - c) / t

A lever 15 metres in length is pivoted at one end. A load of 750 N is suspended from the other end. What force must be applied at the midpoint of the lever in order to obtain equilibrium?

d) 1,500 N

Calculate the area of insulation in square m required to cover a boiler drum which is equipped with hemispherical heads. The diameter of the drum is 84 cm and 4 m in length from one end to the other.

d) 10.556

A vehicle starts off from rest and reaches a velocity of 80 km/h in 12 seconds. If the velocity increases uniformly, how far will the train travel in the first 12 seconds?

d) 133.33 m

A machine is used to lift a load of 2 kN a distance of 3 m and the effort applied is 400 N. What distance will the effort move if the efficiency of the machine is 80%?

d) 18.75 m

If a force of 200 kN is moved a distance of 15 m in 15 seconds, what power is developed?

d) 200 kW

An object is dropped from a height of 45 m. What will its velocity be on impact?

d) 29.71 m/s

A supply fan is driven by an electric motor by means of V-belts. The pulley on the motor shaft is 90 mm in diameter and rotates at 1,800 rpm. The diameter of the pulley on the fan shaft is 300 mm. What is the speed of the fan in rpm?

d) 540

Find the force required to start a 1 ton object moving along a surface with a coefficient of friction of 0.62.

d) 6,082.2 N

A 8 m bar is pivoted at 5 m from the left end. A force of 15 N is applied downward on the left end and a force of 20 N is applied downward on the right end. What would be the clockwise and counter-clockwise moments and in which direction would the bar rotate?

d) 75 Nm counter-clockwise, 60 Nm clockwise, counter-clockwise rotation

A mass of 400 kg is moved a horizontal distance of 30 m due to a force of 300 kN. The amount of work done is

d) 9,000 kJ

A block and tackle system has 6 pulleys in each of two blocks (12 pulleys total). If a downward effort of 260 N is required to raise a load of 300 kg calculate the efficiency of the system.

d) 94.3%

010100020021000D Which of the following statements about force is false? a) Force is the push exerted on a body. b) Force may make a body move. c) Force is the pull exerted on a body. d) No force is required to stop a body. e) Force may make a body stop.

d) No force is required to stop a body.

An effort of 3 kN is required to move a mass of 2,000 kg in a certain simple machine. If the mass is raised 1.5 m while the effort moves 12 m find the velocity ratio (VR), the actual mechanical advantage (MA), and the efficiency (EFF) of the machine.

d) VR = 8, MA = 6.54, EFF = 81.8 %

Solve the following equation for r, [4(Pi)r ^3] / 3 = V

d) cubed root[3V / 4(Pi)]

Solve the following equation for b, 2 [b - (q + s)] / q = s

d) sqr[qs + (q + s)]

A vector quantity has: a) both numerical size and the necessary units of the quantity b) both direction and necessary units of the quantity c) direction, magnitude and necessary units of the quantity d) magnitude and necessary units of the quantity e) magnitude only

direction, magnitude and necessary units

Which of the following statements about inclined planes is false? a) A ramp is an inclined plane. b) Work input = work output + work wasted c) A screw is an inclined plane. d) Work is wasted in friction. e) No work is wasted in producing heat.

e

A 12 m long bar is pivoted on the right end and a force of 150 N is applied upwards on the left end. The moment of force is

e) 1.8 kNm

A body moves from A due east 5 m to B, then from B due north 6 m to C and finally from C due west 8 m to D. Calculate the total distance covered from A to D.

e) 19 m

A simple machine is required to raise 1 tonne of stone a vertical distance of 30 m. If the efficiency of the pulley is 100% how much work must be done on the pulley to raise the stone?

e) 294.27 kJ

An object is thrown directly downwards from a height of 60 m with an initial velocity of 11 m/s. What will be its velocity on impact?

e) 36.03 m/s

A body with a mass of 2 tonnes is moving at 100 km/h. What would be the vertical height that the body could climb before coming to rest?

e) 39.3 m

A plane is flying at 56 km/h at a bearing of 65 degrees. After flying for 3 hours the plane heading is changed to a bearing of 90 degrees. After flying for a further 1 hour at 56 km/h what is the plane's bearing from its original position?

e) 71 degrees

A simple wheel and axle has a wheel diameter of 3 m and an axle diameter of 25 cm. What effort is required to raise 850 kg if the efficiency is 87%?

e) 798.7 N

A car travels a total of 350 km. The journey involves a total of 3 hours driving time and 45 minutes of stop time. What is the average journey speed?

e) 93.3 km/h

In the case of static friction if the downward force between the surfaces is doubled then the friction will: a) decrease by half b) remain constant c) increase by twice as much d) be eliminated e) none of the above

increase 2x

The unit of measure of work as used in the SI system is

joules

The unit of measure of power used in the SI systems is

kilowatts/ watts

The ability to do work due to an object's motion is defined as:

kinectic energy

An object at rest with a mass of 68.5 kg is at a height of 65 m above the earth's surface. What is its kinetic energy? a) 4.45 kJ b) 4.37 kJ c) 34.25 kJ d) 38.6 kJ e) none of the above

none of them

Lines at right angles to each other are said to be __________ to each other.

perpendicular

__________ energy is the ability of a body to do work by virtue of its position.

potential

Rate of doing work is defined as:

power

Force acting in a direction at right angles to a surface, divided by the surface area, is defined as:

pressure

A single vector which can replace a system of vectors and has the same effect is called a:

resultant

To start a body moving which of the following must be overcome? a) kinetic friction b) static friction c) fluid friction d) rolling friction e) normal force

static

The internal resistance developed to counteract an external force is defined as a) strain b) stress c) ultimate strength

stress

For a pivot or lever, the product of Force multiplied by a perpendicular distance from the point of rotation, is defined as:

turning moment

m/s is the SI unit for:

velocity

Which of the following is not a scalar quantity? a) velocity b) length c) volume d) time e) area

A

A simple machine is one which receives energy by means of a single applied force, and produces work by means of __________.

A single out put force

A lever is used to move a load of 10 kN by applying an effort of 1,000 N. What is the mechanical advantage of the lever?

10

In a lifting machine, the effort applied moves a distance of 5 m while the load moves 50 mm. What is the velocity ratio?

100

If three boilers each have a pressure of 130 kPa, the pressure in the steam header will be

130 kpa

A 5 m long bar is pivoted on the left end and a force of 10 N is applied downwards on the right end. The moment of force is

50 Nm clockwise

A force of 120 kN is exerted uniformly over an area of 0.2 square metres. What is the pressure?

600 kpa

An effort of 400 N is required to raise a mass of 100 kg in a certain machine. If the mass is raised 4 m while the effort moves 12 m, find the efficiency of the machine.

82%

9 5 Solve the following equation for r, s = (6y / a r)

9 5 e) 6y /sa