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2 years ago

Efficiency of a machine is always less than 100% why?

Physics

1 answer:

kifflom [539]2 years ago

7 0

The reason the efficiency is always less than 100% is because there is always some sort of friction in the machine.

Answer: because of friction

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Finish A 16 N force is applied to an object and 96 J of work is done. How far was the object moved?

Lina20 [59]

Answer:

$\boxed {\boxed {\sf 6 \ meters}}$

Explanation:

Work is the product of force and distance.

$W=F*d$

We know that 96 Joules of work were done and a 16 Newton force was applied to the object.

W= 96 J
F= 16 N

Substitute the values into the formula.

$96 \ J= 16 \ N * d$

First, let's convert the units. This will make cancelling units easier later in the problem. 1 Joule (J) is equal to 1 Newton meter (N*m), so the work of 96 Joules equals 96 Newton meters.

$96 \ N*m= 16 \ N * d$

Now, solve for distance by isolating the variable, d. It is being multiplied by 16 Newtons and the inverse of multiplication is division. Divide both sides of the equation by 16 N.

$\frac {96 \ N*m}{16 \ N}= \frac{16 \ N *d}{16 \ N}$

$\frac {96 \ N*m}{16 \ N}=d$

The units of Newtons cancel.

$\frac {96}{16} \ m = d$

$6 \ m = d$

The object moved a distance of <u>6 meters.</u>

3 0

3 years ago

A professor's office door is 0.91 m wide, 2.0 m high, and 4.0 cm thick; has a mass of 25 kg; and pivots on frictionless hinges.

olasank [31]

Answer:

F= 5.71 N

Explanation:

width of door= 0.91 m

door closer torque on door= 5.2 Nm

In order to hold the door in open position we need to exert an equal and opposite torque, to the door closer torque, on the door.

so wee need to exert 5.2 Nm torque on the door.

If we want to apply minimum force to exert the required torque we need to apply force perpendicularly on the door knob (end of door) so that to to greater moment arm.

T= r x F

T= r F sin∅

F= T/ (r * sin∅)

F= 5.2/ (0.91 * 1)

F= 5.71 N

5 0

3 years ago

A young hockey player stands at rest on the ice holding a 1.3-kg helmet. The player tosses the helmet directly in front of him w

navik [9.2K]

Answer

given,

initial speed of hockey player= 0 m/s

mass of the helmet, m = 1.3 Kg

initial speed of the helmet, u = 0 m/s

final speed of the helmet, v = 6 m/s

recoil speed of the hockey player, v' = 0.25 m/s

we need to calculate the mass of the hockey player, M = ?

using conservation of momentum

m u + M u' = M v' + m v

initial speed of ice skater is zero

1.3 x 0 + M x 0 = M x (-0.25) + 1.3 x 6

negative sign is taken because recoil velocity is in opposite direction

0 = -0.25 M + 7.8

0.25 M = 7.8

M = 31.2 Kg

Hence, the mass of the young hockey player is equal to 31.2 Kg

5 0

3 years ago

8. What is the frequency of green light waves that have a wavelength of 5.2 x 10-7 m.? The speed of light is 3.0 x 108 m/s

o-na [289]

Answer:

$f=5.76\times 10^{14}\ Hz$

Explanation:

We need to find the frequency of green light having wavelength o $5.2\times 10^{-7}\ m$ . It can be calculated as follows :

$c=f\lambda\\\\f=\dfrac{c}{\lambda}\\\\f=\dfrac{3\times 10^8}{5.2\times 10^{-7}}\\\\f=5.76\times 10^{14}\ Hz$

So, the required frequency of green light is equal to $5.76\times 10^{14}\ Hz$ .

4 0

3 years ago

Why are plane mirrors and convex mirrors unable to form real images

Schach [20]

Because it reverses an image there for making the objects appear on opposite side

4 0

3 years ago