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3 years ago

An object on earth weighs 120 N. What is it’s mass ?

Physics

2 answers:

inna [77]3 years ago

7 0

Weight = (mass) x (gravity)

120 N = (mass) x (9.8 m/s²)

Mass = (120 N) / (9.8 m/s²)

Mass = 12.24 kg (B)

Ainat [17]3 years ago

4 0

Answer:

12.24 kg would be your answer

Explanation:

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The force of gravity on a 60 kg woman is 588 N. The woman also exerts a gravitational force on

bulgar [2K]

Answer:

the same 588 N

Explanation:

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1 year ago

A catapult launches a test rocket vertically upward from a well, giving the rocket an initial speed of 80.6 m/s at ground level.

kow [346]

Before the engines fail, the rocket's altitude at time t is given by

$y_1(t)=\left(80.6\dfrac{\rm m}{\rm s}\right)t+\dfrac12\left(3.90\dfrac{\rm m}{\mathrm s^2}\right)t^2$

and its velocity is

$v_1(t)=80.6\dfrac{\rm m}{\rm s}+\left(3.90\dfrac{\rm m}{\mathrm s^2}\right)t$

The rocket then reaches an altitude of 1150 m at time t such that

$1150\,\mathrm m=\left(80.6\dfrac{\rm m}{\rm s}\right)t+\dfrac12\left(3.90\dfrac{\rm m}{\mathrm s^2}\right)t^2$

Solve for t to find this time to be

$t=11.2\,\mathrm s$

At this time, the rocket attains a velocity of

$v_1(11.2\,\mathrm s)=124\dfrac{\rm m}{\rm s}$

When it's in freefall, the rocket's altitude is given by

$y_2(t)=1150\,\mathrm m+\left(124\dfrac{\rm m}{\rm s}\right)t-\dfrac g2t^2$

where $g=9.80\frac{\rm m}{\mathrm s^2}$ is the acceleration due to gravity, and its velocity is

$v_2(t)=124\dfrac{\rm m}{\rm s}-gt$

(a) After the first 11.2 s of flight, the rocket is in the air for as long as it takes for $y_2(t)$ to reach 0:

$1150\,\mathrm m+\left(124\dfrac{\rm m}{\rm s}\right)t-\dfrac g2t^2=0\implies t=32.6\,\mathrm s$

So the rocket is in motion for a total of 11.2 s + 32.6 s = 43.4 s.

(b) Recall that

${v_f}^2-{v_i}^2=2a\Delta y$

where $v_f$ and $v_i$ denote final and initial velocities, respecitively, $a$ denotes acceleration, and $\Delta y$ the difference in altitudes over some time interval. At its maximum height, the rocket has zero velocity. After the engines fail, the rocket will keep moving upward for a little while before it starts to fall to the ground, which means $y_2$ will contain the information we need to find the maximum height.

$-\left(124\dfrac{\rm m}{\rm s}\right)^2=-2g(y_{\rm max}-1150\,\mathrm m)$

Solve for $y_{\rm max}$ and we find that the rocket reaches a maximum altitude of about 1930 m.

(c) In part (a), we found the time it takes for the rocket to hit the ground (relative to $y_2(t)$ ) to be about 32.6 s. Plug this into $v_2(t)$ to find the velocity before it crashes:

$v_2(32.6\,\mathrm s)=-196\frac{\rm m}{\rm s}$

That is, the rocket has a velocity of 196 m/s in the downward direction as it hits the ground.

3 0

3 years ago

You have seen magnets sticking to the refrigerator door, or maybe in your science class room. They attract metal items, for exam

DENIUS [597]

Answer:

B) shrinks

Explanation:

The magnetic force is a force exerted between two magnets, or two magnetic materials, or also on an electric charge moving in a magnetic field.

If we talk about magnetic material, the magnetic field they generates can be represented using a dipole: essentially, they have a north pole (where the lines of the field go out) and a south pole (where the lines of the field go in).

Also, the lines spread apart as we move away from the magnet itself. This means that the strength of the field (and so, the intensity of the force) decreases as we move away from the magnet.

Using this description, we can now understand that when we move the paper clip further from the magnet, the force exerted on the clip decreases, as the magnetic field becomes weaker. So, the correct answer is B.

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3 years ago

Rather than ascribing the increased kinetic energy of the stone to the work of gravity, we now (when using potential energy rath

Sophie [7]

Answer:

Change/ Potential

Explanation:

Work is the amount of energy required to perform an action that is for a force to cause a displacement.

From work-energy theorem, work done by body is equal to change in its kinetic energy.

Work of gravity is basically the potential energy stored in the body due to gravity. From the law of conservation of mechanical energy, increased kinetic energy comes from the change of the potential energy of the stone.

8 0

2 years ago

Rocks are elastic too! Explain how elasticity and Harry Reid's elastic rebound theory lead to a better understanding of earthqua

ANEK [815]

After the great 1906 San Francisco earthquake, geolophysicistHarry Fielding Reid examined the displacement of the ground surface along the San Andreas Fault. He concluded that the quake must have been the result of the elastic reboundof the strain energy in the rocks on either side of the fault.
strain energy is 0. 5x force x (compression) X (compression)
There is a lot of force and a bit of compression when rocks squash up against other rocks causing earthquakes

7 0

2 years ago