Work = force x distance. So the answer would be 200x50=10000 joules
Remember your kinematic equations for constant acceleration. One of the equations is
, where
= final position,
= initial position,
= initial velocity, t = time, and a = acceleration.
Your initial position is where you initially were before you braked. That means
= 100m. You final position is where you ended up after t seconds passed, so
= 350m. The time it took you to go from 100m to 350m was t = 8.3s. You initial velocity at the initial position before you braked was
= 60.0 m/s. Knowing these values, plug them into the equation and solve for a, your acceleration:
Your acceleration is approximately .
I’d say 4 because running a mile in 6 minutes is better than what most people can do and that will really make your heart rate go up
Take Sally's position to be the origin, and up-the-ramp to be the positive direction. The ball travels a distance <em>x</em> in time <em>t</em> of
<em>x</em> = <em>u</em> <em>t</em> + 1/2 (- 3.7 m/s²) <em>t</em>²
where <em>u</em> is the ball's initial velocity.
Its velocity <em>v</em> at time <em>t</em> is
<em>v</em> = <em>u</em> + (- 3.7 m/s²) <em>t</em>
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Let <em>T</em> be the time it takes for the ball to reach the second person 19.6 m up the ramp. At this time, the ball attains a velocity of 4.9 m/s, so that
4.9 m/s = <em>u</em> + (- 3.7 m/s²) <em>T</em>
<em>T</em> = (<em>u</em> - 4.9 m/s) / (3.7 m/s²)
Substitute this into the distance equation, with <em>x</em> = 19.6 m, and solve for <em>u</em> :
19.6 m = <em>u</em> (<em>u</em> - 4.9 m/s) / (3.7 m/s²) + 1/2 (- 3.7 m/s²) ((<em>u</em> - 4.9 m/s) / (3.7 m/s²))²
<em>u</em> ≈ 13 m/s