Answer:
thickness of ice melted = 1.242*10^{-3} m
Explanation:
power delivered = V*I = 12 * 28 = 336 Watts
.
heat delivered = power * time = 336 W * 300 seconds = 168000 Joules
.
mass of ice melted
mass of ice melted = 97200 J / 335000 J/kg = 0.5014 kg
.
volume of ice melted = mass / density = 0.5014 / 917 = 5.46*10{-4} m3
.
thickness of ice melted = volume / area = 5.46*10{-4} / 0.44 = 1.242*10^{-3} m
Answer:
6.02 s
Explanation:
We can write the position of the stock car as:
where
is the acceleration of the stock car.
The sport car instead starts its motion only 1.3 s afterwards, therefore its position at time t can be written as
where
is the acceleration of the sport car
(we can verify indeed that when t = 1.3 s, ).
The sport car reaches the stock car when the two positions are equal:
Rewriting the equation,
This is a second-order equation with two solutions:
t = 0.73 s
t = 6.02 s
We discard the first solution since we are only interested in the times > 1.3 s, therefore the sport car overcomes the stock car after
6.02 seconds.
A beam of laser is directed at a reflecting surface put on the moon when the beam of laser is reflected a receiver on the each measure the time since the beam was sent till it was received. Laser is simply light so it has constant velocity in vacuum ~ air (c = 3 x 10^8 m/s)
to find the distance:
t : time measured between launching the beam and receiving it
d : distance
d = ct