Answer:
given,
initial velocity = 11.5 m/s
acceleration = 0.5 m/s²
time = 7 s
a) using equation of motion
v = u + a t
v = 11.5 + 0.5 × 7
v = 15 m/s
b) 
s = 92.75 m
distance traveled by racer with final velocity
d = 300 - 92.75
= 207.25 m
time spend to travel 207.25
t = 13.82 s
total time spent to travel 300m
t = 7 + 13.82
t = 20.82 s
time required to travel 300 m with initial velocity
= 26.09 s
time saved due to acceleration
t = 26.09 - 20.82 = 5.27 s
c) second racer is 5 m apart from the first one
distance traveled by the second racer till first one finishes the race
distance behind the leader
d = 300 -5 -245.676 = 49.34 m
time behind the winner
Answer:
Swimmer A
Explanation:
The time required for a swimmer to cross a river is equal to the width of the river which is divided by the magnitude of the component of the velocity which is parallel to the width of the river.
In the given context, all the three swimmers A, B and C swims in a different angle relative to the direction of the flow of river. The swimmer A swims straight at a direction perpendicular to the direction of current of the river across the width of the river, so A will have the largest velocity component which is parallel to the width of the river. So the time taken by swimmer A will be the least to cross the river.
There are four laws of thermodynamics.
Zeroeth Law of Thermodynamics: Two systems in thermal equilibrium with a third system are in thermal equilibrium to each other.
First Law of Thermodynamics: The change in a system's internal energy is equal to the difference between heat added to the system from its surroundings and work done by the system on its surroundings.
Second Law of Thermodynamics: It is impossible for a process to have as its sole result the transfer of heat from a cooler body to a hotter one.
Third Law of Thermodynamics: The entropy of a perfect crystal at absolute zero is exactly equal to zero.
You have to know what the temperature of your suroundings first and then you can melt it with the tools you need. yeah that's another thing know what tools you need and then be safe!:D
