A 0.60-kg block initially at rest on a frictionless, horizontal surface is acted upon by a force of 9.0 N for a distance of 2.0 m. How much farther would the force have to act for the block to have 72 J of kinetic energy?
work = energy
72 J / 9 N = 8 m
It's not correct, that´s what the platform says
Did not subtract work already done
9*2 = 18 J
72 - 18 = 54
54/9 = 6 meters
@Damon thanks a lot!
You are welcome.
To find out how much farther the force would have to act for the block to have 72 J of kinetic energy, we need to use the work-energy principle.
The work done on an object by a force can be calculated using the equation:
Work = force x distance x cos(theta),
where:
- Work is the work done on the object in joules (J),
- Force is the applied force in newtons (N),
- Distance is the displacement of the object in meters (m),
- theta is the angle between the applied force and the direction of motion.
In this case, the force is acting horizontally on a frictionless surface, so the angle between the force and the direction of motion is 0 degrees. Therefore, the equation becomes:
Work = force x distance.
Given that the force is 9.0 N and the distance is 2.0 m, we can calculate the work done:
Work = 9.0 N x 2.0 m = 18 J.
Now, we need to find how much farther the force would have to act for the block to have 72 J of kinetic energy.
The work done on the object is equal to the change in kinetic energy of the object. So:
Work = ΔKE.
Given that the initial kinetic energy of the block is zero, we can write the equation as:
18 J (work done) = 72 J (change in kinetic energy).
To find the change in kinetic energy, we subtract the initial kinetic energy from the final kinetic energy:
72 J - 0 J = 72 J.
Therefore, the force would have to act for an additional distance to achieve a change in kinetic energy of 72 J.