Answer:
A calorimeter uses the temperature change of water to determine the <u>specific heat </u> of another substance.
Explanation:
Here's the formula for the distance covered by an accelerating body in some amount of time ' T '. This formula is incredibly simple but incredibly useful. It pops up so often in Physics that you really should memorize it:
D = 1/2 a T²
Distance = (1/2)·(acceleration)·(time²)
This question gives us the acceleration and the distance, and we want to find the time.
(9,000 m) = (1/2) (20 m/s²) (time²)
(9,000 m) = (10 m/s²) (time²)
Divide each side by 10 m/s²:
(9,000 m) / (10 m/s²) = (time²)
900 s² = time²
Square root each side:
<em>T = 30 seconds</em>
1. 168.1 Hz
To find the apparent frequency heard by the driver in the car, we can use the formula for the Doppler effect:
where
f is the original sound of the horn
v is the speed of sound
is the velocity of the observer (the driver and the car), which is positive if the observer is moving towards the source and negative if it is moving away
is the velocity of the sound source (the train), which is positive if the source is moving away from the observer and negative otherwise
In this problem we have, according to the sign convention used:
Substituting, we find:
2. 
The speed of light can be calculated as
where
d is the distance travelled
t is the time taken
In this problem:
is the total distance travelled by the laser beam (twice the distance between the Earth and the Moon)
t = 2.60 s is the time taken
Substituting in the formula,
