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Vlad [161]
3 years ago
11

50W of power is generated using 100J of work to move a box onto a shelf. How long did it take to move the box from the floor to

the shelf?
Physics
1 answer:
svetoff [14.1K]3 years ago
5 0

Answer: time t = 2 seconds

Explanation:

Given that

Power P = 50W

Energy E = 100J

How long did it take to move the box from the floor to the shelf ? This implies time taken.

Power is defined as the rate at which work is done. I.e

P = W.D/t

Where work done = energy

50 = 100/t

Make t the subject of formula

t = 100/50

t = 2 second

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A rotating fan completes 1200 revolutions every minute. consider the tip of a blade, at a radius of 0.19 m. through what distanc
ser-zykov [4K]

The tip of the fan moves through the outer side of the circle.

So it moves a distance of perimeter of circle in one revolution.

Perimeter of circle = 2\pir, where r is the radius of circle.

In this case radius of circular motion = 0.19 meter

So perimeter of circle = 2\pi*0.19 = 0.38\pi = 1.194 m

So distance does the tip move in one revolution = 1.194 meter

5 0
3 years ago
You have been hired to design a spring-launched roller coaster that will carry two passengers per car. The car goes up a 12-m-hi
Vlada [557]

Answer:

Vmax=11.53 m/s

Explanation:

from conservation of energy

      E_A} =E_{B}

     Spring potential energy =potential energy due to elevation

   0.5*k*x²= mg(h_{B}-h_{A} )=mgh

   0.5*k*2.3²= 430*9.81*6

         k=9568.92 N/m

For safety reason

                                 k"=1.13 *k= 1.13*9568.92

                                    k"=10812.88 N/m

agsin from conservation of energy

      E_A} =E_{C}

    spring potential energy=change in kinetic energy

   0.5*k"*x²=0.5*m*V_{max}^{2}

      10812.88 *2.3²=430*V_{max}^{2}

           V_{max}=11.53 m/s

5 0
3 years ago
Identify two ways in which friction is not useful in science​
kiruha [24]

Answer:

  • Friction between brakes and the wheels of a car or bicycle helps the vehicles slow down.
  • If you do not lubricate your bike regularly with oil, the friction in the chain and axles increases.
8 0
3 years ago
A trapeze artist swings in simple harmonic motion with a period of 3.8 s.
pogonyaev
As we know that time period of simple pendulum is given as

T = 2π √L/g

here we know that

T = 3.8 s

now from above equation we know that

T² = 4π² (L/g)

now on rearranging the above equation we will have

L = gT² / 4π²

now plug in all data into it

L = (9.8) (3.8)² / (4) (3.14)²

so the length of the cable must be 3.6 m
7 0
3 years ago
How does Lenz's Law illustrate the concept that "you can't get
Crazy boy [7]

Answer:

When there is a change in magnetic flux linkage through a loop of wire, an electromotive force is induced in the loop, according to the Faraday-Newmann-Lenz Law:

\epsilon=-\frac{N\Delta \Phi}{\Delta t}

where

N is the number of turns in the loop

\Delta \Phi is the change in magnetic flux through the loop

\Delta t is the time elapsed

The negative sign in the formula represents Lenz's Law, and tells us about the direction of the electromotive force.

In fact, the negative sign means that the direction of the induced emf is such that to oppose to the change in the magnetic flux that originated the induced emf.

This is a consequence of the law of conservation of energy: no energy can be created out of nowhere. In fact, when the emf is induced in the loop, electrical energy appears in the circuit; however, this electric energy cannot come out of nowhere. Instead, it is just "created" from the transformation of some other form of energy (for instance, the mechanical energy that is used to move the loop in the magnetic field, and changing its magnetic flux).

The negative sign in Lenz's Law tells exactly this: the direction of the induced emf is such that it opposes the initial change in magnetic flux that generated the induced emf, so that overall the total energy is conserved.

5 0
2 years ago
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