Answer:
displacement
Explanation:
Hookes Law describes the elastic properties of materials only in the range in which the force and displacement are proportional (displacement = change in length).
Answer:
Attractive Property – Magnet
Explanation:
attracts ferromagnetic materials like iron, cobalt, and nickel. Repulsive Properties – Like magnetic poles repel each other and unlike magnetic poles attract each other. Directive Property – A freely suspended magnet always points in a north-south direction.
Answer:

Explanation:
Given that,
The spring constant of spring 1, 
The motion of the object on spring 1 has twice the amplitude as the motion of the object on spring 2, 
As the magnitude of the maximum velocity is the same in each case, it means the maximum kinetic energy is same in each case. In other words, the total energy is same.




So, the spring constant of spring 2 is 920 N/m. Hence, this is the required solution.
Metals, especially iron, have this form of electron cloud around it. When it's placed in a magnetic field these electrons line up
The force needed to the stop the car is -3.79 N.
Explanation:
The force required to stop the car should have equal magnitude as the force required to move the car but in opposite direction. This is in accordance with the Newton's third law of motion. Since, in the present problem, we know the kinetic energy and velocity of the moving car, we can determine the mass of the car from these two parameters.
So, here v = 30 m/s and k.E. = 3.6 × 10⁵ J, then mass will be

Now, we know that the work done by the brake to stop the car will be equal to the product of force to stop the car with the distance travelled by the car on applying the brake.Here it is said that the car travels 95 m after the brake has been applied. So with the help of work energy theorem,
Work done = Final kinetic energy - Initial kinetic energy
Work done = Force × Displacement
So, Force × Displacement = Final kinetic energy - Initial Kinetic energy.

Thus, the force needed to the stop the car is -3.79 N.