Ask question

Ask question

All categories

4 years ago

12

A motor has the electrical energy equivalent to 400. joules of work. It can lift a 5.0 kg mass 2.0 meters. Calculate the work do

ne by the motor.

2 answers:

vovikov84 [41]4 years ago

7 0

Answer : Work done, W = 98 J.

Explanation :

It is given that,

The electrical energy equivalent to 400. joules of work.

The mass that is lifted by the motor, m = 5 kg

Height, h = 2 m

The work done by the motor is given by :

$W=mgh$

g is acceleration due to gravity

$W=5\ kg\times 9.8\ m/s^2\times 2\ m$

$W=98\ J$

So, the work done by the motor is 98 J

Hence, this is the required solution.

nordsb [41]4 years ago

5 0

Work is defined as force*displacement and the force is mass*gravity so roughly 50N and displacement is 2 meters so total work down is 100joules

You might be interested in

What is the upper block's acceleration if the coefficient of kinetic friction between the block and the table is 0.13?

IgorLugansk [536]

Let us assume that pulley is mass less.

Let the tension produced at both ends of the pulley is T.

We are asked to calculate the acceleration of the block.

Let the masses of two bodies are denoted as $m_{1} \ and\ m_{2}\ respectively$

$Let\ m_{1} =1 kg\ and\ m_{2} =2 kg$

As per this diagram, the body having mass 1 kg is moving downward and the body having mass 2 kg is moving on the surface of the table.

Let the acceleration of each block is a .

For body having mass 1 kg:

The net force acting on 1 kg body will be-

$m_{1} g-T=m_{1} a$ [1]

Here tension in the rope will be vertically upward and weight of the body will be in vertical downward direction.

For body having mass 2 kg:

The coefficient of kinetic friction $[\mu]=0.13$

$Hence\ the\ frictional\ force\ F=\mu N$

$F=\mu m_{2} g$

Hence the net force acting on the body having mass 2 kg-

$T-\mu m_{2} g=m_{2} a$ [2]

Here the tension of the rope is towards right i.e along the direction of motion of the 2 kg block and frictional force is towards left.

Combining 1 and 2 we get-

$m_{1} g-T=m_{1}a$ [1]

$T-\mu m_{2}g= m_{2} a$ [2]

---------------------------------------------------

$[m_{1} -\mu m_{2} ]g=[m_{1} +m_{2} ]a$

$a=\frac{m_{1}-\mu m_{2}} {m_{1}+ m_{2}}*g$

$a=\frac{1-[2*0.13]}{1+2} *9.8\ m/s^2$

$a=\frac{0.74}{3} *9.8\ m/s^2$

$a=2.417 m/s$ [ans]

6 0

3 years ago

Read 2 more answers

An electrical current flowing through a filament bulb causes it to get hot. Explain why this

sergij07 [2.7K]

Answer:

The reason the filament heats up is because it has a high resistance, which means that as electrons move through the filament, they lose a lot of energy.

First, what is current? Current is comprised of electrons moving through an electric field from a high electric potential to a lower potential. For the current to decrease then, something would need to happen to the electrons that go into the light bulb. If 1 electron goes into the light bulb, then at the end of everything I need to still have 1 electron someplace. So how do electrons passing through the bulb make light?

Incandescent light bulbs have a small filament which when heated begins to glow and emit light. The reason the filament heats up is because it has a high resistance, which means that as electrons move through the filament, they lose a lot of energy. You can think of it as walking on a sidewalk compared to walking in waist deep water. A wire is like a sidewalk. It has some resistance, but it is so tiny that it can generally be ignored which is why wires are useful in electronic circuits. The high resistance of the light bulb is like trying to walk through waist deep water. Here energy is being taken from the electrons because of the interactions with the atoms in filament which causes those atoms to heat up, which in turn makes them emit light.

The light bulb is not doing anything to the electrons, so we expect then that any electrons going into the bulb should come out the other side. Since current is just flowing electrons, current stays the same.

Since current is the same on both sides, we know that the electrons are all moving together. Think of it like being in a big loop of people. Since everyone is in a big line you could imagine that you could only move as fast as the slowest person in the line. If everyone is on a big loop of sidewalk then everyone could run around in a circle. This is like having a large current in a loop of wire, or what we call a short. To put the equivalent of a lightbulb into our human circuit, imagine that one section of the sidewalk dips into a pool of water. Now everyone is stuck going as fast as the people trudging through the water. This is why current everywhere in a circuit is smaller when a resistor is introduced. As people trudge through the water they have to work hard to get through the water and they use energy. In a circuit, this energy comes from the voltage source, like a battery. The battery loses energy because it has to "pull" the electrons through the high resistance, and this is why the voltage drops across the light bulb

7 0

3 years ago

I need help by today

babymother [125]

The answer is B. Well it's the best answer.

6 0

4 years ago

HNO3 (aq) + H20 (1) ► NO3- (aq) + H30+ (aq)

vodomira [7]

Answer:

It's H3O+.

Explanation:

The H3O+ ion in the solution is what gives it its acidic properties ( sour taste, low pH , for example). Its known as the hydronium ion.

8 0

3 years ago

The end of a horizontal rope is attatched to a prong of an electricity driven tuning fork that vibrates at 100hz. The other end

Darina [25.2K]

here since string is attached with a mass of 2 kg

so here tension force in the rope is given as

$T = mg$

here we will have

$T = 2(9.8) = 19.6 N$

now we will have speed of wave given as

$v = \sqrt{\frac{T}{\mu}}$

here we will have

$v = \sqrt{\frac{19.6}{0.75\times 10^{-2}}}$

$v = 16.33 m/s$

now we know that frequency is given as

F = 100 Hz

now wavelength is given as

$\lambda = \frac{v}{F}$

$\lambda = \frac{16.33}{100} = 0.16 m$

so wavelength will be 0.16 m

5 0

3 years ago