Answer: - 452.088joule
Explanation:
Given the following :
Mass of water = 12g
Change in temperature(Dt) = (11 - 20)°C = - 9°C
Specific heats capacity of water(c) = 4.186j/g°C
Q = mcDt
Where Q = quantity of heat
Q = 12g × 4.186j/g°C × - 9°C
Q = - 452.088joule
Believe it or not white clouds can be both opaque and transparent depending on the volume and mass within that cloud. The heavier the cloud, the more opaque it'll seem, but the lighter the cloud is, it'll seem transparent-
measures angular displacement per unit time. Its units are therefore degrees (or radians) per second.
Complete question:
A child sits in a wagon with a pile of 0.64-kg rocks. If she can throw each rock with a speed of 7.5 m/s relative to the ground, causing the wagon to move, how many rocks must she throw per minute to maintain a constant average speed against a 3.9-N force of friction
Answer:
The number of rocks per minutes thrown is 49 rocks/min
Explanation:
Given;
mass of the rock, m = 0.64 kg
speed of the rock, v = 7.5 m/s
frictional force,
= 3.9 N
For an object to move at a constant speed, the applied force must be equal to the frictional force.

where;
is the applied force
N/t is the number of rocks per minutes thrown
Substitute the given parameters;

Approximately 49 rocks/min
Answer:

Explanation:
Dimensions of mattress 100 cm by 194 cm by 14 cm
= Mass of mattress = 4 kg
= Density of water = 
g = Acceleration due to gravity = 
Volume of mattress

Weight of water displaced is equal to the buoyant force
Mass of water

Mass of person would be

Weight of the person would be

The air mattress could hold a person that weighs up to
.