4 kg block is attached to a spring, and undergoes simple harmonic motion with a period of 0.35 s. The total energy of the system is 2.5 J. It assumes that there is no air friction where the block is oscillates at maximum displacement between A and -A. Calculate, (a) frequency of the motion​

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.

Abookcase has a mass of 38 kg and the coefficient of friction between it and the floor is 0.82 what is the maximum force of friction between the bookcase and the floor a 372n b 305n c 412n d 449n

Explain why electric current cannot exist if a current doesn't have a voltage source.