Answer: The specific heat capacity of water is 4,200 Joules per kilogram per degree Celsius (J/kg°C). This means that it takes 4,200 J to raise the temperature of 1 kg of water by 1°C. Lead will warm up and cool down fastest because it doesn't take much energy to change its temperature.
Explanation:
We add the values on each of the riders:
300 + 20 + 8
= 328 grams
Answer:

Explanation:
As is showed at the figure annexed, we can solve this problem finding the relation between the girl displacement and the shadow displacement.
Relation the triangles (see figure annexed):

We derive in order to find the speed of the shadow, because:
dx/dt: shadow's speed
dy/dt: girl's speed

Answer:
Time of flight=3.5 seconds
Speed at maximum height is 0
Explanation:
Φ=60°
initial velocity=u=20m/s
Acceleration due to gravity=g=9.8 m/s^2
Total time of flight=T
Final speed=v
question 1:
T=(2 x u x sinΦ)/g
T=(2 x 20 x sin60)/9.8
T=(2 x 20 x 0.8660)/9.8
T=34.64/9.8
T=3.5 seconds
Question 2
Speed at maximum height is 0
When it is not moving or on the ground