A 63 kg astronaut drifting with 7.0 m/s to the right with
respect to a spacecraft uses a jetpack to slow down.
Suppose it takes 14.0 s to come to a stop with respect to the spacecraft. What is the force exerted by the jetpack?

What are atoms of the same element with varying number of neutrons

A0.580-kg rock is tied to the end of a string and is swung in a circle with a radius of 0.500 meters. the velocity of the rock is 4.50 m/s. what is the centripetal force acting on the rock? 15.5 n 5.22 n 69.8 n 23.5 n

The atoms in a nickel crystal vibrate as harmonic oscillators with an angular frequency of 2.3 × 1013 rad/s. the mass of a nickel atom is 9.75 × 10-26 kg. what is the difference in energy between adjacent vibrational energy levels of nickel? (h = 6.626 × 10-34 j • s, , 1 ev = 1.60 × 10-19 j)