Answer:


Explanation:
Let the mass of the other car is "m" and its kinetic energy is

now the mass of the first car is two and half times and its kinetic energy is half that of other car
so we will have



now speed of both cars is increased by value of 9 m/s
so now we will have same kinetic energy for both cars





so speed of first car is


Answer:
0.786 Hz, 1.572 Hz, 2.358 Hz, 3.144 Hz
Explanation:
The fundamental frequency of a standing wave on a string is given by

where
L is the length of the string
T is the tension in the string
is the mass per unit length
For the string in the problem,
L = 30.0 m

T = 20.0 N
Substituting into the equation, we find the fundamental frequency:

The next frequencies (harmonics) are given by

with n being an integer number and f being the fundamental frequency.
So we get:



Answer:
1371.4watt
Explanation:
from power=energy/time
BUT energy=force times distance
The object that goes through chemical change, changes completely to where you can not change it back to its original form. Physical change you can undo
C. element only one substance