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3 years ago

Which changes in an electric motor will make the motor stronger? Check all that apply.

Physics

2 answers:

Doss [256]3 years ago

7 0

Answer:

using a stronger permanent magnet

increasing current in the electromagnet

decreasing the distance between the magnets

Explanation:

As we know the working of magnet is such that when current flows in the coil then due to strong magnetic field the coil will have tendency to rotate.

This is due to the torque on the coil which is given by

$\tau = NiABsin\theta$

now if we need to make the motor to be more strong then we need more torque on it which will be increased by

B = due to stronger magnet or by placing the magnets more closer to each other

i = by increasing the current in the coil

Blababa [14]3 years ago

4 0

Using a stronger magnet; Increasing the current in the magnet; Decreasing the distance between the magnets

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1 point

BaLLatris [955]

Answer:1

Explanation:

7 0

3 years ago

A ball is shot from the ground straight up into the air with initial velocity of 42 ft/sec. Assuming that the air resistance can

Volgvan

Answer:

Maximum height of the ball, h(t) = 27.56 m

Explanation:

It is given that, a ball is shot from the ground straight up into the air with initial velocity of 42 ft/sec.

The height of the ball as a function of time t is given by :

$h(t)=h_o+v_ot-16t^2$

h₀ is initial height, h₀ = 0

So, $h(t)=42t-16t^2$ .........(1)

For maximum/minimum height, $\dfrac{dh(t)}{dt}=0$

$42-32t=0$ ...(2)

t = 1.31 s

Differentiating equation (2) wrt t

h''(t) = -32 < 0

So, at t = 1.31 seconds we will get the maximum height.

Put the value of t in equation (1)

$h(t)=42\times 1.31-16\times (1.31)^2$

h(t) = 27.56 m

Hence, this is the required solution.

7 0

4 years ago

Track and field is an individual sport.<br> True or False?

mars1129 [50]

Most events in track and field are individual except relay races. Therefore, it would probably be true.

7 0

3 years ago

Read 2 more answers

Physics is the study of matter and energy and their relationships.<br><br> True<br> False

prohojiy [21]

False because the physics is like a science and it’s like a math

8 0

3 years ago

Read 2 more answers

A circular saw blade with radius 0.175 m starts from rest and turns in a vertical plane with a constant angular acceleration of

ANEK [815]

Answer:

The distance the piece travel in horizontally axis is

L=3.55m

Explanation:

$a=2 \frac{rev}{s^{2}} \\h=0.820m\\r = 0.125 m
\\d=150rev$

$d= 155 rev = 155(2\pi ) = 310\pi rad$

$a= 2.0 \frac{rev}{s^{2} } = 2.0(2\pi ) = 4.0\pi \frac{rev}{s^{2} }$

$d=d_{i}+vo*t+\frac{1}{2}*a*t^{2} \\ di=0\\vo=0\\d=\frac{1}{2}*a*t^{2}\\t=\sqrt{\frac{2*d}{a}}\\t=\sqrt{\frac{2*310 rad}{4\frac{rad}{s^{2}}}} \\t=12.449$

$w=a*t\\w=4\frac{rad}{s^{2}}*12.449s\\ w=49.79 \frac{rad}{s}$

Now the angular velocity is the blade speed so:

$V=w*r\\V=49.79 \frac{rad}{s}*0.175m\\V=8.7 \frac{m}{s}$

assuming no air friction effects affect blade piece:

time for blade piece to fall to floor

$t=\sqrt{\frac{2*h}{g}}\\t=\sqrt{\frac{2*0.820m}{9.8\frac{m}{s^{2} } }}\\t=0.409s$

Now is the same time the piece travel horizontally

$L=t*V\\L=0.409s*8.7\frac{m}{s}\\L=3.55m$

blade piece travels HORIZONTALLY = (24.5)(0.397) = 9.73 m ANS

6 0

4 years ago