Answer:
B. The presence of an unbalanced force(e.g friction) causes a moving object to stop.
Explanation:
As the friction is that force that can stop the sled upon reaching the levelled surface so the option b is correct.
Answer:
v=77.62 m/s
Explanation:
Given that
h= - 300 m
speed of the bird ,u= 5 m/s
Lets take Speed of the berry when it hit the ground = v m/s
we know that ,if object is moving upward
v² = u² - 2 g h
u=Initial speed
v=Final speed
h=Height
Now by putting the values
v² = u² - 2 g h
v² = 5² - 2 x 10 x (-300) ( take g = 10 m/s²)
v² =25 + 20 x 300
v² ==25 + 6000
v² =6025
v=77.62 m/s
Therefore the final speed of the berry will be 77.62 m/s.
Work= Force in the direction of displacement*displacement.
You know the force in the direction of displacement (horizontally) and the displacement. So,
W=130*11=1430
Therefore, the work done is 1,430 Joules
The question doesn't describe any experiment. If the same experiment is repeated, no matter how many times, the acceleration due to gravity will remain the same as it was during the non-existent original experiment, and will have no effect on anything.
One way is speed=distance divided by time