Energy
The two types of nonrenewable energy
The definition for Work is the amount of ______
What is energy transferred?
The greater power is A kettle that can use 3000J per minute or a kettle than can use 3000J every 30 seconds
3000J every 30 seconds
Show
A box with a 5N force pushing it to the right.
box with arrow pointing to right with 5N
What organelle is needed in plants for photosynthesis?
Chloroplasts
What is the formula for calculating kinetic energy?
Ke = 1/2(m)(v)2
Name an example of mechanical work and electrical work
What is pushing a cart and lighting a house
What is the formula for power
Power = change of energy over time
What is the formula for calculating force
F = m x a
What pigment is in red blood cells to assist in transporting oxygen around the body?
haemoglobin
What is the energy store when 2 clouds are oppositely charged electrically and they come together
electrostatic
A gardener pushes a wheelbarrow with 200 N of force for 15 m. How much work does she do?
What is 3,000 J
What is the units for power
Watts
If a 10 kg object accelerates at 2 m/s22 \, m/s^22m/s2, what is the amount of force acting on it is this
20N
An atom has an overall weight of 56. It has 27 protons. How many neutrons and electrons does it have?
Protons = 27, Neutrons = 29, Electrons = 27
This renewable energy source relies on underground reservoirs of steam and hot water, but it is only practical in regions near tectonic plate boundaries
Geothermal Energy
A crane lifts a 1,200 N steel beam straight up 15 m. At the same time, a worker pushes with 200 N horizontally, but the beam doesn’t move sideways. How much total work is actually done on the beam?
What is 18,000 J? (Only the upward force contributes; horizontal work = 0)
A cyclist is metabolising energy in their body at a rate of 51kJ per minute. They are pushing the pedals of the bicycle with a power of 200W. What is the efficiency of the cyclist’s body when pedalling?
51000J/min = 51000/60 = 850W
A rocket of mass 5,000 kg accelerates upward at 9.8 m/s2. How much net force is acting on it?
49,000N
What is the mass number of Vanadium (23 protons, 28 neutrons, 23 electrons)
51
A scientist drops a 560g hammer from a height of 162cm to the ground on the moon. The moon’s gravity is 6 times smaller than that of the Earth. What is the GPE?
0.56 x (9.8/6) x 0.162 = 0.15J
A worker pushes a crate with a force of 500 N, but it only moves 0.5 m before stopping. Compare the work done here to the work done if the crate had moved 5 m
250 J for 0.5 m and 2,500 J for 5 m
An elevator moves between the ground floor and first floor in 6s. Each person requires 1715J of work to be able to reach the first floor. An empty elevator requires 4000J of energy to lift itself to the first floor. How much power is required to lift one person in the elevator to the first floor?
(4000 + 1715) / 6 = 952.5W
According to Newton’s Second Law, if the net force on an object doubles while its mass stays the same, this happens to the object’s acceleration.
What is the acceleration also doubles?
Describe two ways in which the stomach digests food
The stomach churns food (physical digestion).
It produces gastric juice, which contains enzymes and hydrochloric acid (chemical digestion).