A soccer player runs across a soccer field. a. If the soccer player runs with a speed of 4.6 m/s, how long does it take him to r
un 60 m? b. It takes the soccer player 3 seconds to reduce his speed to 3.1 m/s. What is his acceleration? c. The soccer player is running at a speed of 4 m/s when he slides on the ground, coming to a stop in a distance of 2 m. What was his acceleration? d. The soccer player accelerates from rest at a rate of 3.1 m/s2. How far does he run in 1.5 seconds? Physics
b. acceleration= (the change in velocity/speed)/(time) this is the same as a=Δv/t<span> a= unkown </span>Δv= (final speed - initial speed) = 3.1m/s - 4.6m/s= -1.5m/s t=3 seconds a=Δv/t= -1.5/3= -0.5m/s² answer: the soccer player decelerated by 0.5m/s². This means his speed is decreasing by 0.5m/s². We know it is decreasing because the answer is negative.
c. list given information: final velocity/speed(FS)= 0m/s initial velocity/speed(IS)= 4m/s distance(d)= 2m time(t)= UNKOWN acceleration(a)= UNKOWN (side note: velocity and speed are almost the same thing. The difference between the two words is that velocity usually has a direction and can be negative. Speed cannot be negative. If your problems use the word "speed" I would recommend you continue to use the word "speed" as well. I wanted to clarify this so that you didn't think I was saying to divide velocity by speed.)
Equation: (final speed²)= (inital speed²)+ 2(distance)(acceleration) FS²=IS²+2da (0²)= (4²)+ 2(2)a 0=16+4a -4a=16 a= -4m/s² answer: The deceleration(decreasing acceleration) is 4m/s². This is because the speed was changing at a rate of negative 4 meters per second squared until reaching a final speed of 0m/s.
d. List given information: Initial speed: 0m/s (we know he started from "rest" which means his IS was 0) Final speed: UNKNOWN time= 1.5seconds distance= UNKOWN acceleration= 3.1m/s²
