20m away
the dog was 60m away from. you subtract 40m since it is 10m/s x 4 seconds
Answer:
Work done, W = 6 J
Explanation:
It is given that,
Force of gravity acting on the book, weight of the book is 15 N
We need to find the work done in lifting the book straight up for a distance of 0.4 meters.
The weight of the book is acting in downward direction and the book is lifted straight up, it means angle between them is 180 degrees. Work done is given by :

So, the magnitude of work done in lifting the book is 6 joules.
Explanation:
Mass of bumper cars, 
Initial speed of car A, 
Initial speed of car Z, 
Final speed of car A after the collision, 
We need to find the velocity of car Z after the collision. Let it is equal to
. Using the conservation of momentum as :




So, the velocity of car Z after the collision is (-12 m/s). Hence, this is the required solution.
Answer:
55%
Explanation:
take efficiency=power output/power input multiply by 100%
Answer:
by a rocking chair, a bouncing ball, a vibrating tuning fork, a swing in motion, the Earth in its orbit around the Sun, and a water wave.
Explanation: