All categories

2 years ago

A 10-kg dog is running with a speed of 5.0 m/s. what is the minimum work required to stop the dog in 2.40 s?

Physics

1 answer:

Tasya [4]2 years ago

3 0

<h3><u>Answer;</u></h3>

<em>Work = 125 joules </em>

<h3><u>Explanation and solution</u>;</h3>

Work is the product of force and the distance covered. Therefore, Work = force × distance.

Work is measured in joules.
Work is also a change in energy, such that work is done when energy changes, so when kinetic energy, or potential energy changes the there is work being done.

Thus; kinetic energy = work done

Kinetic energy = 1/2mv²

= 1/2 × 10× 5²

= 5 × 25

= 125 joules

Hence, work done is 125 joules.

You might be interested in

Why do we balance chemical equations

antiseptic1488 [7]

So it could follow the correct mass for the atom

5 0

2 years ago

A child’s toy that is made to shoot ping pong balls consists of a tube, a spring (k = 18 N/m) and a catch for the spring that ca

UkoKoshka [18]

Answer:

The height is 3.1m

Explanation:

Here we have a conservation of energy problem, we have a conversion form eslastic potencial energy to gravitational potencial energy, so:

$E_e=\frac{1}{2}K*x^2\\E_e=\frac{1}{2}18N/m*(9.5*10^{-2}m)^2\\E_e=0.081J$

then we have only gravitational potencial energy when the ball is at its maximun height.

$E_g=m*g*h$

because all the energy was transformed Eg=Ee

$h=\frac{0.081J}{9.8m/s^2*m}$

searching the web, the mass of a ping pong ball is 2.7 gr in average. so:

$h=\frac{0.081J}{9.8m/s^2*(2.7*10^{-3}kg)}\\h=3.1m$

6 0

2 years ago

Which statement best describes the law of conservation of energy?

Phantasy [73]

<span>The correct option is C. Energy cannot be created or destroyed. This statement is known as law of conservation of energy, and it implies that whenever a certain form of energy does change, the loss of this form of energy must have converted into an another type of energy. A typical example is an object falling to the ground: initially, the object has gravitational potential energy. As the object falls down, it loses potential energy (since its altitude from the grounf decreases), but it acquires kinetic energy (because its velocity increases). In this example, potential energy has converted into kinetic energy, but the total energy of the object has remained constant.</span>

8 0

3 years ago

Read 2 more answers

The platform height for Olympic divers is 10 m. A 60 kg diver steps off the platform to begin his dive.

azamat

Answer:

a) Ep = 5886[J]; b) v = 14[m/s]; c) W = 5886[J]; d) F = 1763.4[N]

Explanation:

The potential energy can be found using the following expression, we will take the ground level as the reference point where the potential energy is equal to zero.

$E_{p} =m*g*h\\where:\\m = mass = 60[kg]\\g = gravity = 9.81[m/s^2]\\h = elevation = 10 [m]\\E_{p}=60*9.81*10\\E_{p}=5886[J]$

Since energy is conserved, that is, potential energy is transformed into kinetic energy, the moment the harpsichord touches water, all potential energy is transformed into kinetic energy.

$E_{p} = E_{k} \\5886 =0.5*m*v^{2} \\v = \sqrt{\frac{5886}{0.5*60} }\\v = 14[m/s]$

The work is equal to

W = 5886 [J]

We need to use the following equation and find the deceleration of the diver at the moment when he stops his velocity is zero.

$v_{f} ^{2}= v_{o} ^{2}-2*a*d\\where:\\d = 2.5[m]\\v_{f}=0\\v_{o} =14[m/s]\\Therefore\\a = \frac{14^{2} }{2*2.5} \\a = 39.2[m/s^2]$

By performing a sum of forces equal to the product of mass by acceleration (newton's second law), we can find the force that acts to reduce the speed of the diver to zero.

m*g - F = m*a

F = m*a - m*g

F = (60*39.2) - (60*9.81)

F = 1763.4 [N]

3 0

2 years ago

Describe one practical use of a concave mirror.

Tatiana [17]

Answer:

Here are some uses...

Explanation:

Uses of convex mirror:

It is used in supermarkets and stores for surveillance.

It it is used as rear view mirror in automobiles.this is due to the reason that a convex mirror provides a wider field of view than a plane or concave mirror.

Uses of concave mirror:

It is used in torches.

They are used in headlights of vehicles to send parallel rays to infinity , in shaving mirror to get an enlarged image of the face and also by dentists to see a bigger image of the tooth / teeth .

Mark as brainliest if helped thanks!

7 0

3 years ago

Read 2 more answers