The runners have just started a race. They started at rest and are getting faster.
1 answer:
A. Acceleration is positive and speed is increasing.
<h3>Further explanation</h3>The motion performed by a runner is part of a uniformly accelerated motion with constant acceleration.
Equation used
vf = final velocity
vi = vo = initial velocity
When a runner moves from rest, his speed will increase from being at rest (vi=0) and then move with a constant acceleration(a), and as soon as he crosses the finish line his acceleration will decrease (experience a deceleration ⇒a=- ) and decrease his speed until it finally stops
Velocity and speed are different because velocity itself is a vector quantity that takes into account direction and displacement, while speed is a scalar quantity (only distance).
So the speed does not take positive or negative values because it involves direction, while acceleration takes positive and negative values (deceleration) because it takes direction.
You might be interested in
Question: The question is incomplete. Below is the complete question and the answer;
While ethanol (CH3CH2OH is produced naturally by fermentation, e.g. in beer- and wine-making, industrially it is synthesized by reacting ethylene CH2CH2) with water vapor at elevated temperatures. A chemical engineer studying this reaction fills a 50.0 L tank at 22. °C with 24. mol of ethylene gas and 24. mol of water vapor. He then raises the temperature considerably, and when the mixture has come to equilibrium determines that it contains 15.4 mol of ethylene gas and 15.4 mol of water vapor The engineer then adds another 12. mol of water, and allows the mixture to come to equilibrium again. Calculate the moles of ethanol after equilibrium is reached the second time. Round your answer to 2 significant digits.
Answer:
Number of moles of ethanol = 11 mol
Explanation:
SEE THE ATTACHED FILE FOR THE CALCULATION
