John pushes his brother danny on a skateboard. john applies a force of 150 n and danny's acceleration is 1.2 m/s^2. what is the combined mass of danny and his skateboard

Asap i'm in class rn a 1,000-kg car is traveling 20 m/s on a flat stretch of road. it gets to a hill and coasts uphill until it stops. how high up the hill does the car travel? givens: equation: 1/2mv2initial=mghfinal solve for h. plug & chug, label.

Cathy is pedaling down a steep hill on her bicycle and wants to be able to coast up the next hill, which is 25 meters high, without pedaling. cathy and her bicycle have a mass of 75 kg. assuming her bicycle is 100% efficient, what would her speed have to be?

In a hydrogen molecule there are a total of four charges, 2 protons in the two nuclei, and 2 electrons. how many unique charge-pairs are there (without double counting)?