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3 years ago

A car traveling comes to a stop at a red light.How many forces are taking place?

Physics

1 answer:

charle [14.2K]3 years ago

6 0

i think it depends on the speed rate

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Which is an advantage of AC over DC power?

Zanzabum

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3 years ago

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How to separate a mixture of iron ad copper pieces using an electromagent

aleksandr82 [10.1K]

Answer:

Suck up the iron using the electromagnet.

Explanation:

Iron is magnetic and copper is not. So copper will be

unaffected by the magnet. After extracting the iron,

open the switch. The electromagnet will lose its

magnetism and the iron fillings will fall off..

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2 years ago

A 216-m-wide river flows due east at a uniform speed of 2.2 m/s. A boat with speed of 7.9 m/s relative to the water leaves the s

Mademuasel [1]

Answer:

The magnitude of the velocity of boat w.r.t ground is 6.2015 m/s

Solution:

As per the question;

Width of the river, w = 216 m

Uniform speed of boat due east, $u_{x} = 2.2\hat{i} m/s$

Angle in north west direction, $\theta = 34^{\circ}$

Velocity of the boat relative to water, $v_{bw} = 7.9m/s$

Now,

Velocity of the boat relative to the water is given by:

$v_{bw} = -7.9cos34^{\circ}\hat{i} + 7.9sin34^{\circ}\hat{j}$

$v_{bw} = - 6.55\hat{i} + 4.42\hat{j} m/s$

Also, velocity of water w.r.t ground is $v_{wg} = u_{x} = 2.2\hat{i} m/s$

Now,

Magnitude of the velocity of boat w.r.t ground is given by:

$v_{bg} = v_{bw} + v_{wg}$

$v_{bg} = - 6.55\hat{i} + 4.42\hat{j} + 2.2\hat{i}$

$v_{bg} = - 4.35\hat{i} + 4.42\hat{j} m/s$

$|v_{bg}| = \sqrt{(- 4.35)^{2} + (4.42)^{2}} = 6.2015\ m/s$

7 0

3 years ago

A man has a weight of 100 Newtons. How much work is done if he climbs 4meters up a ladder?

Aliun [14]

Answer:

400 J

Explanation:

Work is done when a force that is applied to an object moves that object.

The work is calculated by multiplying the force by the amount of movement of an object

W = F * d

here the man has to work against the gravitational field. (against his weight)

F =100 N

Work done = F * d

= 100 * 4

= 400 J

7 0

3 years ago

Please help!! giving a lot of points

Readme [11.4K]

Question 1.

mass = 4500 kg
potential energy (p.e) = 67500 J

now, we know :

=》

$p.e = mgh$

=》

$67500 = 4500 \times 10 \times h$

=》

$67500 = 45000 \times h$

=》

$h = \dfrac{67500}{45000}$

=》

$h = 1.5 \: m$

note : if we take acceleration due to gravity as 9.8, then height = 1.53 m

Question 2.

mass = 4500 kg
kinetic energy = 63000 j

we know,

=》

$k.e = \dfrac{1}{2} mv {}^{2}$

=》

$63000 = \dfrac{1}{2} \times 4500 \times {v}^{2}$

=》

${v}^{2} = \dfrac{63000 \times 2}{4500}$

=》

${v}^{2} = 28$

=》

$v = \sqrt{28}$

=》

$v = 2 \sqrt{7} \: \: ms {}^{ - 1}$

=》

$5.29 \: \: ms {}^{ - 1}$

7 0

2 years ago