Answer:
Kinetic energy is given by:
K.E. = 0.5 m v²
Susan has mass, m = 25 kg
Velocity with which Susan moves is, v = 10 m/s
Hannah has mass, m' = 30 kg
Velocity with which Hannah moves is, v' = 8.5 m/s
<u>Kinetic energy of Susan:</u>
0.5 m v² = 0.5 × 25 kg × (10 m/s)² = 1250 J
<u>Kinetic energy of Hannah:</u>
0.5 m v'² = 0.5 × 30 kg × (8.5 m/s)² = 1083.75 J
Susan's kinetic energy is <u>1250 J </u>and Hannah's kinetic energy is <u>1083.75 J</u>.
Since kinetic energy is dependent on mass and square of speed. Thus, speed has a greater effect than mass. As it is evident from the above example. Susan has greater kinetic energy due to higher speed than Hannah.
Ordinary cells can convert chemical energy to electrical energy only, but rechargeable cells can also store electrical energy into chemical energy and vice versa. You will study more about it in your higher classes. secondary cells can be recharged and used again but dry cells cannot be recharged.
Answer: Seismograph is an instrument that is used to measure the vibration of the earthquake. It is based on seismic waves. X ray is an electromagnetic energy wave that is used for CAT ( computerized axial tomography) scan.
Hence, both seismic wave and X ray are energy waves.
The velocity of seismic waves is different in different media. Similarly, X ray loses its amplitude depending upon the dense layer of the tissue.
Answer:
75.6J
Explanation:
Hi!
To solve this problem we must use the first law of thermodynamics that states that the heat required to heat the air is the difference between the energy levels of the air when it enters and when it leaves the body,
Given the above we have the following equation.
Q=(m)(h2)-(m)(h1)
where
m=mass=1.3×10−3kg.
h2= entalpy at 37C
h1= entalpy at -20C
Q=m(h2-h1)
remember that the enthalpy differences for the air can approximate the specific heat multiplied by the temperature difference
Q=mCp(T2-T1)
Cp= specific heat of air = 1020 J/kg⋅K
Q=(1.3×10−3)(1020)(37-(-20))=75.6J
The bear fell because it slides to the surface of ice due to lack of friction.
One of these theories is that friction<span> causes the liquid layer of water to form on </span>ice<span>. </span>Friction<span> is the force that generates heat whenever two objects slide against each other. If you rub your hands together, you can feel them heat up. That's </span>friction<span> at work. When a </span>skate<span> moves over the surface of </span>ice, the friction<span> between the </span>skate<span> and the </span>ice<span> generates heat that melts the </span>outermost<span> layer of </span>ice<span>.</span>
