Answer:
the work againts gravity is zero (0)
Explanation:
This is because the work is always done, by a force that acts parallel in the direction of the displacement of the body.
In this case, the gravity and the weight of the bag is not acting in the direction of the displacement, therefore there is no work done.
The answer is the second choice
Answer:
Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system.
Explanation:
Answer:
D. Calculate the area under the graph.
Explanation:
The distance made during a particular period of time is calculated as (distance in m) = (velocity in m/s) * (time in s)
You can think of such a calculation as determining the area of a rectangle whose sides are velocity and time period. If you make the time period very very small, the rectangle will become a narrow "bar" - a bar with height determined by the average velocity during that corresponding short period of time. The area is, again, the distance made during that time. Now, you can cover the entire area under the curve using such narrow bars. Their areas adds up, approximately, to the total distance made over the entire span of motion. From this you can already see why the answer D is the correct one.
Going even further, one can make the rectangular bars arbitrarily narrow and cover the area under the curve with more and more of these. In fact, in the limit, this is something called a Riemann sum and leads to the definition of the Riemann integral. Using calculus, the area under a curve (hence the distance in this case) can be calculated precisely, under certain existence criteria.

9. An object which is in circular motion (moving along a circle) is said to be accelerating because it changes it's direction constantly even if it is moving with a constant speed. cuz acceleration is change in either magnitude or direction of an object with respect to time.
therefore, it's still acceleration as change in direction with time.
10. Average speed of an object can be calculated by dividing the total distance covered by an object by time taken to cover that distance.
i.e
it can be re- arranged to find the distance as :
11. speed = 20 m/s : conversion into km/h
distance covered : 4 km = 4000 m
time taken = 200 seconds
12. let's use the first equation of motion to find the acceleration :