Answer:
529.2 N
Explanation:
As we have studied the first law of motion, which states that every action has some reaction, equal in magnitude but having an opposite direction.
The force that is acting on the student will be due to gravitational force, that is equal to his weight.
F=mg: 54kg x 9.8m/s^2 =529.2 N
So the weight of student is exerting downwards towards the stool and land. The stool will also exert a force on the student that will be equal in magnitude but opposite in direction, then it will be 529.2 N.
This is because the student is sitting in a constant state and all the weight is exerted on the stool.
Note: This answer is very generic supposing that all the weight of the student is on stool. But, if we suppose that student's legs are on floor so it means the force of gravity acting on the stool has become less because student's mass on stool is less. So the answer would be a force somehow less than 529.2 N. However, since the question asked normal force, it would be weight of student in general terms.
Hope it helps!
Answer: 14943.5 J
Explanation:
The quantity of heat energy (Q) required to raise the temperature of a substance depends on its Mass (M), specific heat capacity (C) and change in temperature (Φ)
Thus, Q = MCΦ
Given that,
Q = ?
Mass of water = 55.0g
C = 4.18 J/g°C
Φ = 65.0°C
Then, Q = MCΦ
Q = 55.0g x 4.18 J/g°C x 65.0°C
Q = 14943.5 J
Thus, 14943.5 joules of heat is needed to raise the temperature of water.
A base and an Acid always react to form a salt and water
So, HCl + NaOH —> NaCl + HOH
So let's use some equations to represent the data [let R= cost of ring & B= cost of bracelet]
R= B + $ 36 .... (1)
B=
× R ... (2)
By using simultaneous equations to solve for B and R.
Substitute eq. (1) into eq. (2)
B =
× (B + $36)
B =
B +
⇒ B = $48
By substituting value of B into ea (1)
If R = B + $36
R = ($48) + $36
= $84
∴ <span> the total of the two items = R + B
= $84 + $48
</span> = $132
