Hello
Here we must use the equation of motion
v^2 = u^2 + 2as; where v is final velocity, u is initial velocity, a is the acceleratoin and is the distance travelled.
We select this one because the time of collision is unknown to us.
We know the truck stopped so its final velocity is 0; thus v = 0.
Converting the initial velocity to SI units, we get 3.89 m/s.
The distance traveled, s, is 0.062 meters.
Inserting all of these values into the equation,
0 = (3.89)^2 + 2(a)(0.062)
and solving for a, we get a to be
-122.0 ms^(-2)
The negative sign indicates the acceleration is in the opposite direction to the initial motion, which means the truck decelerated. This is consistent with the given condition.
Answer:
If she is walking 30 feet every 10 seconds, that means she is walking 180 feet per minute. Multiply that by the 60 minutes in an hour, means she walks (180x60)= 10,800 feet an hour.
She walks 3 feet a second.
She walks 180 feet a minute.
She walks 10,800 feet an hour.
Explanation:
The kinetic energy of an object is given by:
KE = 0.5mv²
KE = kinetic energy, m = mass, v = speed
Given values:
KE = 0.161J, v = 2.33m/s
Plug in and solve for m:
0.161 = 0.5m(2.33)²
m = 0.059kg
