Q1. To estimate the muzzle speed of a blow dart, fire dart straight up into the air and time how long it takes to come back down. Roughly half of that time is the time for object to decelerate from its initial velocity to motionless. Estimation the initial velocity.
Q2. A 96.0 g lead ball is dropped from rest from a height of 4.85m. The collision between the ball and the ground is totally inelastic.
Suppose the entire ball's kinetic energy goes into heating the ball; find its change in temperature.