Answer:
Explanation:
Option a is correct
If puck and pick constitute a system then the momentum of the system is conserved but not this may not be valid for the puck .
Option e is correct
If puck and pick is the system then momentum is conserved but because of the presence of friction, mechanical energy is not conserved.
Friction will cause the energy to dissipate in heat.
Answer:
The acceleration of the train is 5 m/s².
Explanation:
Given:
let the initial velocity of a train = 5 m/s and
final velocity of a train = 45 m/s
time taken = 8 s
To find:
acceleration: ?
Solution:
We define acceleration as change in velocity per unit time that is the difference between the final velocity and initial velocity divided by time.

On substituting the above values we get the required acceleration

Therefore,the acceleration of the train is 5 m/s².
The answer is refracts parallel to the axis of the lens
Average speed = (total distance covered) / (time to cover the distance)
Total distance = (80m) + (125m) + (45m) = 250 meters
Overall time = 10 minutes
Average speed = (250 meters) / (10 minutes)
<em>Average speed = 25 meters/minute </em>
Since we're only looking for average speed and not velocity, we don't care about any of the directions, and we don't need to calculate Mary's displacement.