Two vectors a is 3i-4j-5k and 6i+2j-5k find angle between a and b

The experiment done in lab is repeated, using a ball that has unknown mass m. you plot your data in the form of f 2 versus m/l, with f in rev/s, m in kg, and l in m. your data falls close to a straight line that has slope 3.19 m/(kg · s2). use g = 9.80 m/s2 and calculate the mass m of the ball.

Difference between natural and artifical magnet

If we decrease the amount of force and keep all other factors the same what will happen to the amount of work