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Westkost [7]
3 years ago
9

A force of 70 N is applied to a 28 kg rock causing it to slow down from 25 m/s to 15 m/s, a change in velocity of 10 m/s. How lo

ng was that force applied?
Physics
1 answer:
maksim [4K]3 years ago
7 0

Answer: 4 s

Explanation:

Given

The applied force is 70 N

mass of the rock is 28 kg

initial velocity u=25\ m/s

final velocity v=15\ m/s

Deceleration provided by force is

a=-\dfrac{70}{28}=-2.5\ m/s^2

using the equation of motion

v=u+at\\\Rightarrow 15=25-2.5t\\\Rightarrow 2.5t=10\\\Rightarrow t=4\ s

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alexgriva [62]

Answer:

0 J

Explanation:

W = Work done on the satellite in circular orbit about earth by earth

F = Force on gravity on satellite by earth

d = displacement of the satellite

\theta = Angle between the force on gravity and displacement = 90

We know that, Work done is given as

W = F d Cos\theta\\W = F d Cos90\\W = F d (0)\\W = 0 J

3 0
3 years ago
How did the magnet’s density measurement using the Archimedes’ Principle compare to the density measurement using the calculated
guapka [62]

Answer:

The two methods will yield different results as one is subject to experimental errors that us the Archimedes method of measurement, the the density measurement method will be more accurate

Explanation:

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5 0
3 years ago
An object is hanging by a string from the ceiling of an elevator. The elevator is moving upward with a constant speed. What is t
xeze [42]

Answer:

The magnitude of the tension in he string is equal to the magnitude of the weight of the object.

Explanation:

According to the Newton's 1st law, An object will remain at rest or in uniform motion in a straight line unless acted upon by an unbalanced force.

In here, the elevator is moving with a constant speed. So the object must have the equal constant speed. Which means, it has a uniform motion. According to Newton's 1st law, the total unbalanced force on the object must be zero . As we know, there are only two forces are on the object and they are,

The tension in string(T)   ,   The weight of the object(W) .

                                  ∴ F    =   0

                                 T  -  W  =   0

So to balanced those forces, the magnitude of the tension in the string must be equal to the magnitude of the weight of  the object.  

       

8 0
3 years ago
The length and mass of the arm are Larm = X1 = 50 cm and Marm = 0.3 kg, X2 = 15 cm, and the mass of the object is MObject = 0.25
max2010maxim [7]

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Explanation: if the system is at equilibrium, sum of the torque will be equal to zero.

But if they are not in equilibrium.

U will find the difference in the two torque

find the attached file for solution

3 0
3 years ago
What happens when two positive charges are near each other?
Westkost [7]
If two positive charges are near each other they will repel each other.
7 0
3 years ago
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