Answer:
Force = mass × acceleration
Acceleration:

From first Newton's equation of motion:

Change = v - u:

Explanation:
A wave having a frequency of 200 Hz means that 200 such waves pass through a point per second.
Answer:
An unbalanced force means that there are more than one forces with different directions or magnitudes affecting the object. In this case, the vector addition of the forces should be done. The vector addition will result a net force. The object will move in the direction of the net force.
Answer: because the ice was cold, and it melted in the tea. So the tea is now cooler.
Explanation:
The average velocity of a car that travels 450 km north in 9.0 h is 5.0 x 10 km/h