Answer:
20g
Explanation:
Given parameters:
Quantity of heat = 240calories
Initial temperature = 80°C
Final temperature = 68°C
Unknown:
Mass of water = ?
Solution;
To solve this problem, we use the expression:
Q = m c (t₂ - t₁)
Q is the quantity of heat
m is the mass
c is the specific heat = 1 cal/g°C
t₂ is the final temperature
t₁ is the initial temperature
Insert the parameters and solve;
Change in temperature is an absolute value
240 = m x 1 x (68 - 80)
m = 20g
Answer:
Explanation:
height lost h = 300 sin60
= 259.8 m .
gravitational potential energy = mgh
= 5000 x 9.8 x 259.8
= 1273 x 10⁴ J
Kinetic energy
= 1/2 mv²
= .5 x 5000 x 60²
= 900 x 10⁴ J
there is loss of kinetic energy = 373 x 10⁴ J.
This loss in energy is due to kinetic friction that came into action when the sled slipped downwards.
The lost energy is converted into heat energy or thermal energy.
