Sandy and Chris stand on the edge of a cliff and throw identical mass rocks at the same speed. Sandy throw her rock horizontally while Chris throws his upward at an angle of 45° to the horizontal. (i) Which one has a higher speed : Sandy’s thorwn rock at the launch or Chris’s rock when it reaches its highest point in its flight? (ii) Which one (sandy’s rock or Chris’s rock has the higher speed right before hitting the ground? : Explain carefully your answer.

Astone is dropped from the upper observation deck of a tower, 250 m above the ground. (assume g = 9.8 m/s2.) (a) find the distance (in meters) of the stone above ground level at time t. h(t) = (b) how long does it take the stone to reach the ground? (round your answer to two decimal places.) s (c) with what velocity does it strike the ground? (round your answer to one decimal place.) m/s (d) if the stone is thrown downward with a speed of 2 m/s, how long does it take to reach the ground? (round your answer to two decimal places.) s

The average time that it takes for the car to travel the first 0.25m is s. the average time to travel just between 0.25 m and 0.50 m is s. given the time taken to travel the second 0.25 m section, the velocity would be m/s.

Which of the following forces require physical contact? tension air resistance friction magnetic force applied force