Answer: The acceleration of the object is 0.67m/s^2 west.
Explanation: Here we are given the initial velocity and final velocity as well as the time taken. Acceleration is the change in velocity per unit time, thus the equation becomes.
a=dv/t
a=vf-vi/t
a=-2.1-4.7/3.9
a= 0.66m/s^2 west
Answer:
4589.05 year
Explanation:
The relation of activity is given by
we have given
Half life 
We know that half life 

So 



Answer:
Momentum is the product of a moving object's mass and velocity . ... When two objects collide the total momentum before the collision is equal to the total momentum after the collision (in the absence of external forces). This is the law of conservation of momentum. It is true for all collisions.
Explanation:
Answer:
(iv), (v), (vi) would be incorrect.
Explanation:
(iv) Force isn't transferred from one colliding object to another, but momentum can be.
(v) An object doesn't stop immediately a force stops acting on it. Think of a thrown ball.
(vi) For an object not to move, it means that the net force on the object is zero, and not necessarily that there are no forces acting on the object. For example, an object could be pushed on one side, and be pushed on the other side with an equal force in the opposite direction. The forces would cancel each other and the net force would be zero.
The rest should be correct.