Answer:
b. 0.20 m/s.
Explanation:
Given;
initial mass, m = 0.2 kg
maximum speed, v = 0.3 m/s
The total energy of the spring at the given maximum speed is calculated as;
K.E = ¹/₂mv²
K.E = 0.5 x 0.2 x 0.3²
K.E = 0.009 J
If the mass is changed to 0.4 kg
¹/₂mv² = K.E
mv² = 2K.E
Therefore, the maximum speed is 0.20 m/s
What happens when the light hits the glass depends on what it was in before it hit the glass.
WHILE it's in the glass, the speed of light doesn't change.
1. is 75 km/h because 150 divided by 2 is 75
3. the second person since he ran the same distance in less time
4. a.True b.False c.True
Answer:
-4,651.42N
Explanation:
Since we are not asked what to find, we can calculate the force applied by the track as shown;
F = ma
F = m(v-u)/t
Substitute the given value
F = 4400(7.6-52)/42
F = 4400(-44.4)/42
F = -4,651.43N
Hence the required force is -4,651.42N
NONE of those choices defines the law of conservation of energy,
and none even describes it. It's as if these choices belong to
a whole different question.
In fact, none of the choices is even a true statement by itself !
A statement that defines the law of conservation of energy
would have to say something like this:
The total amount of energy in any closed system is constant.
The total amount of energy after any event or process is the
same as the total amount was before it.
