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Kinematics
Dynamics
Density
Energy
Pressure
100
A car travels 600 m in 30 s. What is it average speed?
20 m/s
100
What are the three Newton's Laws
Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it (Law of Inertia) The resultant sum of all the forces acting on an object is equal to the mass m of that object multiplied by the acceleration of the object: F = ma. When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body
100
What is the density of 2L of liquid, if its mass is 2.5 kg?
d=1.25kg/L
100
What is the law of conservation of energy?
Energy cannot be made or destroyed, but it can change from one form to another
100
A 200N force is applied over an area of 4m2. What pressure is produced? What would be the pressure if the same force acted on half the area?
P=50Pa Half the area P=100Pa
200
A car takes 8 s to increase its velocity from 10 m/s to 30 m/s. What is its average acceleration?
a=2.5 m/s2
200
A car has a mass of 900 kg. It accelerates from rest at a rate of 1.2 m/s2. What is the force exerted by the engine?
1080 N
200
Aluminium has a density of 2700 kg/m3. What is the density in g/cm3?
d=2.7g/cm3
200
An object has a mass of 6 kg, what is its gravitational potential energy 6 m above the ground?
360J
200
Explain why a tractor's big tyres stop it sinking too far into soft soil
They spread the wight over a large area
300
A truck travelling at 25 m/s puts its brakes on for 4 s. This produces a deceleration of 2 m/s2. What does the truck's velocity drop to?
vf=17m/s
300
What is friction? What are the two types of friction?
The force of friction is a force that resists motion when two objects are in contact. There are two forms of friction, kinetic and static. If you try to slide two objects past each other, a small amount of force will result in no motion. The force of friction is greater than the applied force. This is static friction. If you apply a little more force, the object "breaks free" and slides, although you still need to apply force to keep the object sliding. This is kinetic friction. You do not need to apply quite as much force to keep the object sliding as you needed to originally break free of static friction.
300
Aluminium has a density of 2700 kg/m3, what is the mass of 20 cm3 of aluminium?
m=54g
300
An engine does 1500 j of work with each 5000J supplied. What is its efficiency? What happens with the rest of the energy supplied? What is the power output if the work is done in 3 seconds?
30% It is transmitted to the surrounding air. 500W
300
A rectangular block of mass 30kg measures 0.1m by 0.4m by 1.5m. Calculate the maximum pressure and the minimum pressure
Pmin=500Pa Pmax=7,500 Pa
400
A stone is thrown upwards with an initial velocity of 10 m/s, how long does it take to go down to your hand? What is its maximum height?
t=2s h=5m
400
A 60 kg cyclist moving at 20 m/s applies the breaks, and decelerate at a steady rate of 5 m/s2, until he stops. How long does it take him to stop? What force has he applied? Draw a Free-Body Diagram
t=4s F=300N https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=0ahUKEwif5d-FgubMAhXmA8AKHUAcBzAQjRwIBw&url=http%3A%2F%2Faskthephysicist.com%2Fclassical%2520mechanics.html&bvm=bv.122448493,d.ZGg&psig=AFQjCNFY4yaVHQ0nA5bjwt3f2DE4V1wGTg&ust=1463743012717951
400
A plastic bag filled with air has a volume of 0.008 m3. When air in the bag is squeezed into a rigid container, the mass of the container with air increases from 0.02 kg to 0.03 kg. What is the density of the air?
d=1.25 kg/m3
400
Name four different types of energy that can be transformed into electrical energy in power stations
Solar Nuclear Thermal Kinetic
400
Explain how a hydraulic jack works
Two pistons connected have the same pressure. The The quotient between force and pressure is the same on the two pistons, and therefore a small force over a small surface will produce a big force over a big surface
500
In the planet Potaterturn (g=4 m/s2), an astronaut drops a hammer from a 50 cm height. How long does it take to hit the ground?
t=0.5 s
500
A plane drops a 500 kg package, and air resistance acts on it. If it accelerates at 4 m/s2, what is air resistance?
mg-D=ma D=mg-ma D=5000-2000 D=3000N
500
A balloon contains 2000 m3 of air. When the air is cold, its density is 1.3 kg/m3. When heated, the air expands and some is pushed out of the hole at the bottom, and the density falls to 1.1 kg/m3. What is the mass of air lost?
m=400 kg
500
A 2kg stone is thrown upwards with 2m/s velocity. What is its kinetic energy? What is the maximum height it can reach?
KE=4J GPE=4J=mgh, h=4/20=0.2m
500
The density of salty sea water is 1,035 kg/m3. What would be the pressure on a submarine boat at 100 m depth?
P=dgh=1,035,000Pa=1,035 kPa