Question

In an experiment, a variable, position-dependent force FC) is exerted on a block of mass 1.0 kg that is moving on a horizontal surface. The frictional force between the block and the surface has a constant magnitude of Ff. In addition to the final velocity of the block, which of the following information would students need to test the hypothesis that the work done by the net force on the block is equal to the change in kinetic energy of the block as the block moves from 2 = 0 to z = 5 m?
A The function F(2) for 0 < x < 5 and the value of Fr.

B) The function a(t) for the time interval of travel and the value of F.

C The function F(x) for 0 < x < 5, the block's initial velocity, and the value of F.

D) The function a(t) for the time interval of travel, the time it takes the block to move 5 m, and the value of Ft.

E) The block's initial velocity, the time it takes the block to move 5 m, and the value of F.

Answer 1

Answer:

C) The function F(x) for 0 < x < 5, the block's initial velocity, and the value of Fr.

Explanation:

Yo want to prove the following equation:

$W_N=\Delta K$

That is, the net force exerted on an object is equal to the change in the kinetic energy of the object.

The previous equation is also equal to:

$F(x)x-F_f=\frac{1}{2}m(v_f^2-v_o^2)$    (1)

m: mass of the block

vf: final velocity

v_o: initial velocity

Ff: friction force

F(x): Force

x: distance

You know the values of vf, m and x.

In order to prove the equation (1) it is necessary that you have C The function F(x) for 0 < x < 5, the block's initial velocity, and the value of F.  Thus you can calculate experimentally both sides of the equation.