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Step2247 [10]
3 years ago
7

You hold a metal block of mass 40 kg above your head at a height of 2 m.

Physics
1 answer:
Kitty [74]3 years ago
5 0

Answer:

The work done by gravity is 784 J.

Explanation:

Given:

Mass of the block is, m=40\ kg

Height to which it is raised is, h=2\ m

Acceleration due to gravity is, g=9.8\ m/s^2

Now, work done by gravity is equal to the product of force of gravity and the distance moved in the direction of gravity. So,

\textrm{Work by gravity}=F_g\times h

Force of gravity is given as the product of mass and acceleration due to gravity.

\therefore F_g=mg=40\times 9.8=392\ N. Now,

\textrm{Work by gravity}=F_g\times h=392\times 2=784\ J

Therefore, the work done by gravity is 784 J.

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Determine whether each of the following is exothermic or endothermic and indicate the sign of δh. A. Natural gas burning on a st
Oxana [17]

Answer:

A) exothermic, δh is negative

B) endothermic, δh is positive

C) endothermic, δh is positive

Explanation:

And endothermic process absorbs heat from its sorrounding, cooling the sorrounding down. Whereas an exothermic process releases heat to its sorrounding raising the temperature of the sorrounding system.

5 0
3 years ago
A 3kg box has 45J of gravitational potential energy, how high is it off the ground?
frez [133]

Answer:

1.53m

Explanation:

Given parameters:

Mass of box  = 3kg

Gravitational potential energy  = 45J

Unknown

Height of the box  = ?

Solution:

To solve this problem;

 Gravitational potential energy = mgh

m is the mass

g is the acceleration due to gravity

h is the height

            45  = 3 x 9.8 x h

            h  = 1.53m

7 0
3 years ago
Reaction time is the lapse of time between muscular movement and external stimuli. True or false
riadik2000 [5.3K]
False. reaction time would be lapse of time between external stimuli and muscular movement
3 0
3 years ago
Read 2 more answers
Susan is quite nearsighted; without her glasses, her far point is 34 cm and her near point is 17 cm . Her glasses allow her to v
butalik [34]

Answer:

u=34cm

Explanation:

From the question we are told that:

Far point is V=34 cm

Near point is u=17 cm

Therefore

Focal Length

f=-34cm

Generally the equation for the Lens is mathematically given by

\frac{1}{u}=\frac{1}{f}-\frac{1}{v}

\frac{1}{u}=\frac{1}{-34}-\frac{1}{-17}

u=34cm

5 0
3 years ago
What is the mass of a car that has a kinetic energy if 4,320,000 J moving at 23 m/s?
Alekssandra [29.7K]

Answer:

kinetic energy=1/2mv^2.

which is 4320000=1/2×m×23^2.

which is 4320000=1/2×m×529.

4320000=264.5m.

m=4320000/264.5.

m=16332.70~16333g

4 0
3 years ago
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