A student has 5 small carts, each with a different mass.Placing each of them on a flat, smooth ramp she uses a spring driven plunger to push each cart with a constant force.She measures the amount of time it takes each cart to reach the end of the ramp.She adjusts the amount of force used each time until each of the carts reach the end of the ramp with the same time.This means that each cart will have approximately the same initial acceleration.Which of the graphs below could represent the amount of force needed to push the different carts so they get the same acceleration?

Gravity force causes the clouds of dust and gas to form a protostar. As this attraction force is responsible for gathering and compressing the existing elements in the cloud of gas and dust, heating them during this process.

Then, when the amount of material accumulated by gravitational contraction is large enough, and the temperature and pressure reached high enough, the nuclear fusion process will begin.

To understand it better: The hydrogen nuclei will begin to fuse, generating helium nuclei in the process and releasing huge amounts of energy.

It should be noted that the protostars radiate half of the energy contributed by the gravitational collapse and the other half is invested in heating its core.