Question

when running at a constant horizontal velocity (vx) which of the following must be true?
○ braking impulse > propulsion impulse
○ braking impulse < propulsion impulse
○ none of the above

question 2 1 pts
a negative horizontal reaction force (rx) - time curve is called a
○ propulsion impulse
○ braking impulse
○ none of the above

Explanation:

Step1: Recall Newton's first - law

According to Newton's first law, an object moving at a constant velocity has zero net force acting on it. Impulse is force multiplied by time. For constant horizontal velocity, the net impulse (propulsion impulse - braking impulse) must be zero, so braking impulse = propulsion impulse. Thus, the answer to the first question is none of the above.

Step2: Understand horizontal reaction force

A negative horizontal reaction force acts to slow down an object. Braking impulse is associated with forces that slow down an object. So a negative horizontal reaction force (Rx) - time curve is called a braking impulse.

Answer:

Question 1: none of the above
Question 2: braking impulse