Formula for kinetic energy is 1/2mv^2 so that answer should most probably be 94521.6J
Answer:
1500 m/s
Explanation:
Recall that for a wave,
Speed = frequency x wavelength
here we are given frequency = 500 Hz and wavelength = 3m
simply substitute into above equation
Speed = 500 Hz x 3m
= 1500 m/s
1) 5.79 s
2) 98.4 ft/s
Explanation:
1)
The motion of the car is a uniformly accelerated motion (it means it travels with constant acceleration), so we can find the time it takes for the car to stop by using the following suvat equation:

where
s is the distance travelled
v is the final velocity
t is the time
a is the acceleration of the car
In this problem we have:
s = 285 ft is the distance travelled
is the acceleration of the car (negative since the car is slowing down)
v = 0 ft/s is the final velocity of the car, since it comes to a stop
Solving for t, we find:

2)
The initial speed of the car can be found by using another suvat equation, namely:

where
v is the final speed
u is the initial speed
a is the acceleration
t is the time
In this problem, we have:
v = 0 is the final speed of the car
is the acceleration of the car (negative since the car is slowing down)
t = 5.79 s is the total time of motion (found in part 1)
Therefore, the initial speed of the car is:
