It is the first one. But if you have this question you are not a little boy
Answer:
240000 Joules
Explanation:
Applying,
The work that must be done by the frictional force of the brake to stop the car must be equal to the kinetic energy of the car.
W = mv²/2.................. Equation 1
Where W = work done by the frictional force of the brake, m = mass of the car, v = velocity of the car.
From the question,
Given: m = 1200 kg, v = 20 m/s
Substitute these values into equation 1
W = (1200×20²)/2
W = 240000 Joules
The law of conservation of mass states that mass can be destroyed during a chemical change is TRUE
Answer:
the bar is the top and bottem. the nucleas in the middle and the Spiral arm is the last space
Explanation: