Velocity = displacement (distance)/time
v=80m/4s
v=20m/s
velocity = 20 meters per second
Answer:
It is a instrument used to measure the distance traveled by a vehicle.
Explanation:
This is what it looks like ↓
Answer:
Time taken, 
Explanation:
It is given that, a small metal ball is suspended from the ceiling by a thread of negligible mass. The ball is then set in motion in a horizontal circle so that the thread’s trajectory describes a cone as shown in attached figure.
From the figure,
The sum of forces in y direction is :


Sum of forces in x direction,

.............(1)
Also, 
Equation (1) becomes :

...............(2)
Let t is the time taken for the ball to rotate once around the axis. It is given by :

Put the value of T from equation (2) to the above expression:


On solving above equation :

Hence, this is the required solution.
Answer:
Explanation:
Given that,
Mass of the heavier car m_1 = 1750 kg
Mass of the lighter car m_2 = 1350 kg
The speed of the lighter car just after collision can be represented as follows


b) the change in the combined kinetic energy of the two-car system during this collision

substitute the value in the equation above

Hence, the change in combine kinetic energy is -2534.78J