Work-Energy theorem
What are the 2 equations learnt about the work-energy theorem?
Work=ΔKE =(1/2)m(V^2 - U^2)
Work=ΔPE = mgΔh
A pendulum is raised to eye level. It is then released and allowed to swing down. What type of energy does it start with at its maximum height and what type of energy does it have at the bottom of its swing?
Gravitational potential energy, kinetic energy
What do Conservative Forces do?
The make Work A=Work B (even if path A and B are different)
What is the formula for power?
P = ΔE/Δt
What is the gravitational potential energy of a 3 kg object at a height of 6 meters?
180 Joules
Is the Mechanical Energy the same between one point and the other (of the same path) in presence of friction?
No, because friction implies energy losses
Mention one example of Non-Conservative Force
Friction
How much power does a motor produce if it can transfer 400 Joules of energy in 5 seconds?
80 Watts
What is the gravitational potential energy of a 12 kg object at a height of 4.5 meters?
529.2 Joules
Mr. Whetstone drops a bowling ball from the top of BVT. What type(s) of energy does the bowling ball have when it is halfway down?
Kinetic and gravitational potential
Make one example of Conservative Force
The applied force (Thrust)
How much energy can a car engine produce if it can generate 500 Watts of power for 6 seconds?
3000 Joules
Mr. C is on top of the roof of his house. His mass is 90 kg. If he has 8820 Joules of gravitational potential energy, how high from the ground is he?
10 meters
5.42 m/s
You are travelling by bike. Mention all of the Conservative and Non-Conservative Forces acting during your motion.
Thrust (to push the bike forward) - Conservative
Friction (contact between the wheels and the road) - Non-conservative
Air resistance (Contact between air and you/bike) - Non-Conservative
A 1800 kg car accelerates from 6 m/s to 15 m/s in 3 seconds. How much power is transferred to the car's wheels to accelerate it?
56.7 kW
A hot air balloon has 980,000 Joules of gravitational potential energy. If it is at a height of 1000 meters, what is its mass?
100 kg
A 0.25 kg toy rocket leaves its launch pad on the ground with a velocity of 25 m/s. How high does the rocket reach?
31.89 meters
A ball is falling doward, mention all of the Conservative and Non-Conservative Foorces
Force oif gravity - Conservative
Air-Resistance - Non-Conservative
A solar panel having efficiency = 21 % provides 7500 Joules of electrical energy. How much solar energy does it have to receive ?
35714.28 J of solar (Electromagnetic) energy