Please help!! A single constant force is exerted on an object. The graph describes the objects energy. How much work was done to increase the speed of the object from 1.0 m/s to 3.0 m/s?

A: 1.5 J
B: 2.0 J
C: 4.0 J
D: 4.5 J

C. 4.0 J

Explanation:

Work is equal to the change in kinetic energy or kinetic energy final - kinetic energy initial. 1/2 mv^2 is the equation for kinetic energy. SInce the mass is the same, you don't have to include it when solving. 1/2 times 1^2 = 1/2. 1/2 times 3^2 = 4.5. 4.5 - 0.5 = 4 J

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards