A farmer heaves a 7.56 kg bale of hay with a final velocity of 4.75. What is the kinetic energy of the bale?

kherson [118]

Land surfaces change, erosion happens, the ground collapses, etc.

7 0

3 years ago

Which of the following statements is/are true?Check all that apply.a. A conservative force permits a two-way conversion between

Eddi Din [679]

Answer:

a). A conservative force permits a two-way conversion between kinetic and potential energies.

TRUE

Because there is no energy loss in presence of conservative forces so energy conversion in two ways are possible.

b). A potential energy function can be specified for a conservative force.

TRUE

negative gradient of potential energy is equal to conservative force

$F = -\frac{dU}{dr}$

c). A non-conservative force permits a two-way conversion between kinetic and potential energies.

FALSE

here energy is lost against non-conservative forces

d). The work done by a conservative force depends on the path taken.

FALSE

work done by conservative force is independent of path

e). The work done by a non-conservative force depends on the path taken.

TRUE

work done by non conservative forces depends on path.

f). A potential energy function can be specified for a non-conservative force.

FALSE

It is not defined for non conservative forces

3 0

3 years ago

A man walks along a straight path at a speed of 4 ft/s. A searchlight is located on the ground 6 ft from the path and is kept fo

BARSIC [14]

We are given that,

$\frac{dx}{dt} = 4ft/s$

We need to find $\frac{d\theta}{dt}$ when $x=8ft$

The equation that relates x and $\theta$ can be written as,

$\frac{x}{6} tan\theta$

$x = 6tan\theta$

Differentiating each side with respect to t, we get,

$\frac{dx}{dt} = \frac{dx}{d\theta} \cdot \frac{d\theta}{dt}$

$\frac{dx}{dt} = (6sec^2\theta)\cdot \frac{d\theta}{dt}$

$\frac{d\theta}{dt} = \frac{1}{6sec^2\theta} \cdot \frac{dx}{dt}$

Replacing the value of the velocity

$\frac{d\theta}{dt} = \frac{1}{6} cos^2\theta (4)^2$

$\frac{d\theta}{dt} = \frac{8}{3} cos^2\theta$

The value of $cos \theta$ could be found if we know the length of the beam. With this value the equation can be approximated to the relationship between the sides of the triangle that is being formed in order to obtain the numerical value. If this relation is known for the value of x = 6ft, the mathematical relation is obtained. I will add a numerical example (although the answer would end in the previous point) If the length of the beam was 10, then we would have to