Two pole-vaulters just clear the bar at the same height. the first lands at a speed of 8.27 m/s, while the second lands at a speed of 8.71 m/s. the first vaulter clears the bar at a speed of 0.742 m/s. ignore air resistance and friction and determine the speed at which the second vaulter clears the bar.

How are calculation for velocity and speed different

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".

An element becomes a positively charged ion when itloses protons. loses electrons. gains electrons. gains neutrons.