Answer:
W = 1222.4 J = 1.22 KJ
Explanation:
The work done on an object is the product of the force applied on it and the displacement it covers as a result of this force. It must be noted that the component of displacement in the direction of force should only be used. Hence, the work can be calculated as:
W = F d Cosθ
where,
W = Work Done = ?
F = Force Applied = 64 N
d = Distance Covered by Box = 19.1 m
θ = Angle between force and displacement = 0°
Therefore,
W = (64 N)(19.1 m)Cos 0°
<u>W = 1222.4 J = 1.22 KJ</u>
Explanation:
Given parameters:
Initial velocity = 72km/hr
Final velocity = 0km/hr
Time taken = 25s
Unknown:
Acceleration = ?
Solution:
To solve this problem, convert km/hr to m/s;
1000m = 1km
3600s = 1hr
72km/hr;
1km/hr = 0.278m/s
72km/hr = 0.278 x 72 = 20.02m/s
Acceleration is the change in velocity divided by the time taken;
Acceleration =
Acceleration =
= -0.8m/s
The car is actually decelerating at a rate of 0.8m/s
Work Done = Force x Distance Moved
Work Done = 25 x 15 = 375 Joules