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3 years ago

What is the potential energy of a 20-kg safe sitting on a shelf 0.5 meters

Physics

1 answer:

ki77a [65]3 years ago

8 0

Explanation:

P.E=MGH

Where m is mass

Where G is Acceleration Due to Gravity

Where h is Height

So the parameters are M = 20kg

G = 9.8m/s

H = 0.5meters

P.E= 20x9.8x0.5

=98J.

So Ans. is A= 98J

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Which of these events is an example of resonance?

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An opera singer breaks a thin glass with only the use of her high frequency voice

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2 years ago

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Wilma can mow a lawn in 80 minutes. Rocky can mow the same lawn in 120 minutes. Construct an equation that would allow you to de

xeze [42]

Answer:

$t = 96 minutes$

Explanation:

Time to mow 1 lawn by Wilma is 80 minutes

so work done in 1 minute by Wilma is given as

$W_1 = \frac{1}{80}$

Similarly Rocky mow same lawn in 120 minute

so work done in 1 minute by Rocky is given as

$W_2 = \frac{1}{120}$

now we know that they both worked by "t" time

so total work performed by them

$W = \frac{t}{80} + \frac{t}{120}$

they both mow 2 lawns then it is given as

$2 = (\frac{1}{80} + \frac{1}{120})t$

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3 years ago

If calcium lost two electrons it would have the same number of electrons as

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If Calcium lost two electrons, it would have the same number of electrons as Argon which has 18 electrons.

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2 years ago

A 49 kg bear slides, from rest, 11 m down a lodgepole pine tree, moving with a speed of 3.3 m/s just before hitting the ground.

hichkok12 [17]

Answer:

a) $\Delta U_g=-5.3kJ$

b) $K=0.27kJ$

c) $F_f=0.45kN$

Explanation:

the gravitational potential energy is given by:

$U_g=m.g.h\\$

$\Delta U_g=m.g.h_f-m.g.h_i\\\Delta U_g=49kg*9.8m/s^2*(0m-11m)\\\Delta U_g=-5.3kJ$

The kinetic energy is given by:

$K=\frac{1}{2}m.v^2\\$

the initial kinetic energy is zero because the motion started from rest, so:

$K=\frac{1}{2}*49kg*(3.3m/s^2)^2\\K=0.27kJ$

applying the conservation of energy theorem:

$U_g-W_f=K_f\\W_f=-(\Delta K+\Delta U)\\W_F=5.3kJ-0.27kJ\\W_F=-5.0kJ$

The work done by the friction force is given by:

$W_f=F_f.h.cos(\theta)\\$

the angle of the force is 180 degrees because it's against the movement:

$F_f=\frac{W_f}{h.cos(\theta)}\\\\F_f=\frac{-5.0kJ}{11m.cos(180^o)}\\\\F_f=0.45kN$

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3 years ago

The tip of the fan blade is 0.61 m from the center of the fan. The fan turns at a constant speed and completes 2 rotation every

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Answer:

What is the centripetal acceleration of the tip of the fan blade?

6.0 m/s2

48 m/s2

53 m/s2

96 m/s2

Answer is 96

Explanation:

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3 years ago