A man steps out of a plane at a height of 4000 m above the ground, falls

Explain why a cow that touches an electric fence experiences a mild shock

Minchanka [31]

The voltage exists between the fence and the ground. The cow is grounded. The cow is touching the ground, completing the circuit of electricity. <span>When the cow comes into contact with the fence, it becomes an electric ground which sends an electric current into the cow, through the cow, and into the ground. The pain experienced from the shock is due to the current that flows through the cow.</span>

8 0

3 years ago

A 6 kg box with initial speed 5 m/s slides across the floor and comes to a stop after 1.9 s. What is the coefficient of kinetic

Ilia_Sergeevich [38]

Answer:

$\mu_k=0.27$

Explanation:

According to the free body diagram, in this case, we have:

$\sum F_x:-F_k=ma\\\sum F_y:N=mg$

Recall that the force of friction is given by:

$F_k=\mu_k N$

Replacing and solving for the coefficient of kinetic friction:

$-\mu_kN=ma\\-\mu_k(mg)=ma\\\mu_k=-\frac{a}{g}$

We have an uniformly accelerated motion. Thus, the acceleration is defined as:

$a=\frac{v_f-v_0}{t}\\a=\frac{0-5\frac{m}{s}}{1.9s}\\a=-2.63\frac{m}{s^2}$

Finally, we calculate $\mu_k$ :

$\mu_k=-\frac{-2.63\frac{m}{s^2}}{9.8\frac{m}{s^2}}\\\mu_k=0.27$

4 0

3 years ago

A scientific law is based on repeated inferences made over long periods of time. Please select the best answer from the choices

sergiy2304 [10]

It would be true
I believe

5 0

3 years ago

Read 2 more answers

In free fall, the ___________ of velocity of the object changes

aleksley [76]

Answer:

Magnitude and direction.

Explanation:

Velocity can be defined as the rate of change in displacement (distance) with time. Velocity is a vector quantity and as such it has both magnitude and direction.

Mathematically, velocity is given by the equation;

$Velocity = \frac{distance}{time}$

Gravity is considered to be a universal force of attraction which acts between all objects that has both mass, energy and occupy space. Therefore, it acts in such a way as to bring objects together.

Additionally, the gravity of earth makes it possible for all physical objects to possess weight.

Hence, in free fall, the magnitude and direction of velocity of the object changes.

5 0

3 years ago

A 35 g steel ball is held by a ceiling-mounted electromagnet 3.8 m above the floor. A compressed-air cannon sits on the floor, 4

n200080 [17]

Answer:

Explanation:

Let v is the launch speed of the plastic ball and the angle of projection is θ.

So, in horizontal direction

v Cosθ x t = 4.8 .... (1)

In th evertical direction

1.4 = v Sin θ x t - 0.5 gt² .... (2)

As , v Sin θ x t = 3.8 .... (3) , put in equation (2)

1.4 = 3.8 - 4.9 t²

t = 0.7 s

Put in (1) and (3)

v Cosθ x 0.7 = 4.8

v Cosθ = 6.86

and v Sinθ x 0.7 = 3.8

v Sinθ = 5.43

Now

$v^{2}\left ( Sin^{2}\theta +Cos^{2}\theta \right )=5.43^{2}+6.86^{2}$

v = 8.75 m/s

3 0

3 years ago