Answer:
c.) 25 N
Explanation:
We find the volume of the brick, knowing that the volume of a cube is given by the formula:

being l the side of the cube, which in this case is 10 cm or 0,1 m. Now we find the mass of the object, knowing the density and the Volume of the cube:

We find the weight by multiplying the mass of the object with the gravity constant.

Answer:
The spring force constant is
.
Explanation:
We are told the mass of the ball is
, the height above the spring where the ball is dropped is
, the length the ball compresses the spring is
and the acceleration of gravity is
.
We will consider the initial moment to be when the ball is dropped and the final moment to be when the ball stops, compressing the spring. We supose that there is no friction so the initial mechanical energy
is equal to the final mechanical energy
:

Initially there is only gravitational potential energy because the force of the spring isn't present and the speed is zero. In the final moment there is only elastic potential energy because the height is zero and the ball has stopped. So we have that:

If we manipulate the equation we have that:




Answer: buzzer.
The working principle of a buzzer is the conversion of electrical energy to sound energy.
The switch just cuts or permits the flow of current, the motor convertes electrical or other kind of energy into mechanical energy, a bulb converts electrical energy into light and a battery converts chemical energy into electrical energy.
The electrical energy consumed by a toaster is 0.033 Kwh.
<u>Explanation</u>:
The power utilized by the toaster is 400 W.

The toaster is operated for 5 Minutes.

We know that,

Substitute the values in the above formula to obtain electrical energy,

Electrical energy = 0.4 × 0.083
Electrical energy is 0.033 Kwh.