Answer:
Heat energy required = 252000J or 252KJ.
Explanation:
<u>Given the following data;</u>
Mass = 3kg
Temperature = 20ºC
Specific heat capacity of water = 4200 J/kg°C
To find the heat energy required;
Heat capacity is given by the formula;
Where;
- Q represents the heat capacity or quantity of heat.
- m represents the mass of an object.
- c represents the specific heat capacity of water.
- t represents the temperature.
Substituting into the equation, we have;
Q = 252000 Joules or 252 Kilojoules.
Density is mass per unit volume
remember
p= m/v where v is vol, m is mass and p is density
Answer:
M = 500 J
Explanation:
Given that,
Mass, M = 1000 g = 1 kg
Height, h = 10 m
Potential energy is given by :
P = mgh
P = 1×10×10
P = 100 J
The kinetic energy at ground = 400 J
Mechanical energy = sum of kinetic and potential energy
So,
M = 100 + 400
M = 500 J
So, the mechanical energy of the system is 500 J.
Average speed of the runner is the rate at which the runner covers the total distance. Average speed of the runner in the race is given by,
Average speed = 
Where
Total distance = Distance covered by the runner from initial to final position
Total time = time taken by the runner to cover entire distance
Instantaneous speed is the speed of the runner at the particular moment in the given time. Instantaneous speed is given by,
Instantaneous speed = 
x = position of the runner at time t
t = time taken to cover distance x
Hence, Average speed and instantaneous speed are different for a runner running in the race.
Answer:
Paleontologists have argued for a long time that the demise of the dinosaurs was caused by climatic alterations associated with slow changes in the positions of continents and seas resulting from plate tectonics. Off and on throughout the Cretaceous (the last period of the Mesozoic era, during which dinosaurs flourished), large shallow seas covered extensive areas of the continents. Data from diverse sources, including geochemical evidence preserved in seafloor sediments, indicate that the Late Cretaceous climate was milder than today's. The days were not too hot, nor the nights too cold. The summers were not too warm, nor the winters too frigid. The shallow seas on the continents probably buffered the temperature of the nearby air, keeping it relatively constant.
