Ask question

Ask question

All categories

3 years ago

5

I can raise a bucket of cement mix of mass 12kg through a vertical height of 8m in 10 seconds.Calculate the average power used i

n raising the bucket against the gravitational force?

1 answer:

Andrei [34K]3 years ago

5 0

Explanation:

Power = work / time

Power = force × distance / time

P = (12 kg × 10 m/s²) (8 m) / (10 s)

P = 96 Watts

You might be interested in

An object 2cm high is placed 3cm in front of a concave lens of focal length 2cm, find the magnification?

Simora [160]

Answer:

0.4

Explanation:

A concave lens is a diverging lens, so it will always have a negative focal length. Image distance is always negative for a concave lens because it forms virtual images.

From the lens formula;

1/f = 1/u+ 1/v

- 1/2 = 1/3 - 1/v

1/v = 1/3 + 1/2

v= 6/5

v= 1.2 cm

Magnification = image distance/object distance

Magnification = 1.2cm/3cm

Magnification = 0.4

8 0

3 years ago

A 80 kg skier grips a moving rope that is powered by an engine and is pulled at constant speed to the top of a 25 degrees hill.

zloy xaker [14]

Answer:

$P=28.085\,hp$

Explanation:

Given that:

mass of 1 skier, $m=80kg$

inclination of hill, $\theta=25^{\circ}$

length of inclined slope, $l=220m$

time taken to reach the top of hill, $t=2.3 min= 138 s$

coefficient of friction, $\mu=0.15$

<em>Now, force normal to the inclined plane:</em>

$F_N=m.g.cos\theta$

$F_N=80\times 9.8\times cos25^{\circ}$

$F_N=710.54\,N$

<em>Frictional force:</em>

$f=\mu.F_N$

$f=0.15\times 710.54$

$f=106.58\,N$

<em>The component of weight along the inclined plane:</em>

$W_l=m.g.sin\theta$

$W_l=80\times 9.8\times sin25^{\circ}$

$W_l=331.33\,N$

<em>Now the total force required along the inclination to move at the top of hill:</em>

$F=f+W_l$

$F=106.58+331.33$

$F=437.91\,N$

<em>Hence the work done:</em>

$W=F.l$

$W=437.91\times 220$

$W=96340.80\,J$

<em>Now power:</em>

$P=\frac{W}{t}$

$P=\frac{96340.80}{138}$

$P=698.12\,W$

<u>So, power required for 30 such bodies:</u>

$P=30\times 698.12$

$P=20943.65\,W$

$P=\frac{20943.65}{745.7}$

$P=28.085\,hp$

8 0

3 years ago

A rock slides down from A to B along the inside surface of a frictionless hemispherical bowl. As the rock slides, mechanical ene

DIA [1.3K]

Answer:

the normal force on the rock acts perpendicular to the bowl's surface.

Explanation:

As we know that Normal force is the reaction force of two contact surfaces which always act perpendicular to the contact surfaces

Here we know that the rock is moving inside the bowl

So Normal force on the rock must perpendicular to the surface of the bowl which always passes through the center of the bowl.

Since the rock is moving in vertical plane so it must have two acceleration

1) Tangential acceleration which will increase the magnitude of the speed along the tangential path

2) Centripetal acceleration which will change the direction of the rock

So here only correct option will be

the normal force on the rock acts perpendicular to the bowl's surface.

6 0

3 years ago

What is the largest component of M1?

mariarad [96]

The largest component of M1 is- Currency.

8 0

3 years ago

Why must chemical rxn be balanced

Svetradugi [14.3K]

The chemical equation needs to be balanced so that it follows the law of conservation of mass. A balanced chemical equation occurs when the number of the different atoms of elements in the reactants side is equal to that of the products side. Balancing chemical equations is a process of trial and error.

5 0

3 years ago