Answer:
, assuming that the gravitational field strength is 
.
Explanation:
Notice that both the speed and the direction of motion of this block are constant. In other words, the velocity of this block is constant.
By Newton's Second Law, the net force on this block would be 
. External forces on this block should be balanced. Thus, the magnitude of the (downward) weight of this block should be equal to the magnitude of the (upward) force that the boy applies on this block.
Let 
denote the mass of this block. It is given that 
. The weight of this block would be:
.
Hence, the force that the boy applies on this block would be upward with a magnitude of 
.
The mechanical work that a force did is equal to the product of:
- the magnitude of the force, and
- the displacement of the object in the direction of the force.
The displacement of this block (upward by 
) is in the same direction as the (upward) force that this boy had applied. Thus, the work that this boy had done would be the product of:
- the magnitude of the force that this boy exerted, , and
- the displacement of this block in the direction, .
.
Answer:
60
Explanation:
Translation -
A book weighing 12 N is balanced on a table. Knowing that the static friction coefficient is 0.5, how much is the friction force worth?
Friction force is
f = u * n
f = 0.5 * 12N
f = 60
It reaches 10 or 20 million degrees kelvin but it can get as high as 10 million degrees kelvin
Answer:
p = 4000 kg-m/s
Explanation:
Given that,
The mass of a truck, m = 200 kg
Speed of the truck, v = 20 m/s
We need to find the momentum of the truck. The formula for momentum is given by :
p = mv
so,
So, the momentum of the truck is equal to 4000 kg-m/s.
Batteries supply electrons to the circuit by releasing negatively charged atoms or ions. These ions are produced by the batteries through a chemical reaction that spontaneously occurs within the battery. So the negative end of the battery pushes the ions towards the positive end of the circuit with the help of the voltage. This is why eventually, batteries "run out" when the electrode is used up and the chemical reaction can no longer continue.
