Newton’s first law of motion was a giant leap forward in scientific thought during Newton’s time. Even today, the idea is sometimes difficult at first for people to understand. Which statement is the best example of an object and motion that would make it hard for people to accept Newton’s first law?

A rolling ball eventually slows down and comes to a stop.
A wagon must be pushed before it begins to move.
The heavier the load in a cart, the harder the cart is to turn.
A box does not move when pushed equally from opposite sides.

After the near spacecraft passed mathilde, on several occasions rocket propellant was expelled to adjust the spacecraft's momentum in order to follow a path that would approach the asteroid eros, the final destination for the mission. after getting close to eros, further small adjustments made the momentum just right to give a circular orbit of radius 45 km (45 × 10^3 m) around the asteroid. so much propellant had been used that the final mass of the spacecraft while in circular orbit around eros was only 545 kg. the spacecraft took 1.04 days to make one complete circular orbit around eros. calculate what the mass of eros must be.

Ametal ball with a mass of 0.028 kg is dropped from rest at a height of 1.0 meters above the ground. assuming the energy in the ball is conserved, how much kinetic energy will the ball have when it is 0.5 meters above the ground?

If an atom contains 11 protons in its nucleus, predict the element with the atomic number and electronic configuration. will the number of electrons remain the same during the chemical reaction in such an atom? explain.