How would you calculate the spring constant of an unknown spring?

Isla’s change in velocity is 30 m/s, and hazel has the same change in velocity. which best explains why they would have different accelerations? isla had negative acceleration, and hazel had positive. isla had a different time than hazel. isla had positive acceleration, and hazel had negative. isla went a farther distance than hazel.

An open cart is moving along a straight frictionless horizontal track. when rain starts falling vertically into the cart, what happens to the speed of the cart?

Suppose a wire with a current is pushed upward by a magnetic field. how would the wire move if the direction of the current reversed? explain your answer.