Answer:
0.147 J
Explanation:
The total energy that has been transformed into thermal energy is equal to the loss of gravitational potential energy between the initial situation (bob at h=0.5 m above the ground) and the final situation (bob back but at h=0.45 m above the ground).
Therefore, we have

where
m = 0.3 kg is the mass of the bob
g = 9.8 m/s^2
h1 = 0.5 m is the initial height
h2 = 0.45 m is the final height
Substituting, we find the thermal energy

Therefore, the energy transformed into thermal energy is 0.147 J.
Daniddmelo says it right there, don't know why he got reported.
The potential energy (PE) is mass x height x gravity. So it would be 25 kg x 4 m x 9.8 = 980 joules. The child starts out with 980 joules of potential energy. The kinetic energy (KE) is (1/2) x mass x velocity squared. KE = (1/2) x 25 kg x 5 m/s2 = 312.5 joules. So he ends with 312.5 joules of kinetic energy. The Energy lost to friction = PE - KE. 980- 312.5 = 667.5 joules of energy lost to friction.
Please don't just copy and paste, and thank you Dan cause you practically did it I just... elaborated more? I dunno.
Answer:
it is because it do not produce smoke like fuel from wood.
Answer:
105.1N
Explanation:
According to the newton second law

Since the acceleration is zero, then;

Since;

Given the following
mass of ladder m = 14kg
acceleration due to gravity g = 9.8m/s²
θ = 50°
Substitute

Hence the magnitude of the friction force (in N) exerted on the ladder in the point of contact with the horizontal surface is 105.1N