The runner had an initial vertical velocity of -0.7 m/s and an initial horizontal velocity of 3.6 m/s. If the forces were applied over a period of 0.2 seconds, what are the runner's final vertical and horizontal velocities?

1.26m/s; 4.96m/s

Explanation

Acceleration is defined as the change I'm velocity of an object with respect to time.

Mathematically,

Acceleration (a) = change in velocity (v-u)/time (t)

Where v is the final velocity

u is the initial velocity

From the equation, it can be deduced that;

v = u+at

If the runner had an initial vertical velocity of -0.7 m/s over a period of 0.2seconds, its final velocity;

v = (-0.7)+9.81(0.2) (a=g=9.81m/s²)

v = -0.7+1.962

v = 1.26m/s

If the runner had an initial horizontal velocity of 3 m/s over a period of 0.2seconds, its final velocity;

v = 3+9.81(0.2)

v = 3+1.962

v = 4.96m/s

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

the force represented by vector a is normal force. if the hockey puck is moving to the right, when it is hit with a significant force by the hockey stick the puck will move off in a different direction. correct on edge.