Answer: (d)
Explanation:
Given
Mass of object 
Speed of object 
Mass of object at rest 
Suppose after collision, speed is v
conserving momentum

Initial kinetic energy

Final kinetic energy

So, it is clear there is decrease in kinetic energy . Thus, energy decreases and velocity becomes 2 m/s.
He produced the first orderly arrangement of known elements, he used patterns to predict undiscovered elements
1.cool down
2.activity log
3.specific warm up
4.activities of daily living
5.planned exercise
6.general warm up
Answer:
speed and acceleration
Explanation:
speed is a scalar quantity
acceleration is a vector quantity