Answer:
the energy of the spring at the start is 400 J.
Explanation:
Given;
mass of the box, m = 8.0 kg
final speed of the box, v = 10 m/s
Apply the principle of conservation of energy to determine the energy of the spring at the start;
Final Kinetic energy of the box = initial elastic potential energy of the spring
K.E = Ux
¹/₂mv² = Ux
¹/₂ x 8 x 10² = Ux
400 J = Ux
Therefore, the energy of the spring at the start is 400 J.
As we use the Kinetic energy and the equation is 1/2mv^2, changing its mass will change its speed and its energy. So more mass, more speed more energy. also the gravitational potential energy; mass x gravity x height; more mass and more height more speed as it go down to the slope! Hope it helps!
Answer:

Explanation:
For this case we can use the second law of Newton given by:

The friction force on this case is defined as :

Where N represent the normal force,
the kinetic friction coeffient and a the acceleration.
For this case we can assume that the only force is the friction force and we have:

Replacing the friction force we got:

We can cancel the mass and we have:

And now we can use the following kinematic formula in order to find the distance travelled:

Assuming the final velocity is 0 we can find the distance like this:

Answer:
1 inch = 2.54 cm
12.9 inches= 12.9 x 2.54
= 32.766
= 32.8 cm (approximately)
Hope it helps...
Answer:
90 ohms
Explanation:
1/r = 1/180 + 1/180
1/r= 2/180
take the reciprocal of 2/180 which is 180/2 and its 90 ohms