Work is said to be done when force applied moves a distance in the direction of the force.
The questions here relate to motion and i will try to answer each one.
1) The graph as shown represents a constant negative acceleration.
2) Given that even at constant velocity, an acceleration occurs in circular motion because the direction of motion changes hence as the carousel moves, there is acceleration; change in velocity.
3) From the diagram shown, we can see that a simple machine makes a task easier.
4) The average speed for each lap decreases. This is an example of a(n) inverse relationship.
5) When a stack of books is carried at waist level across a room, work is not being done.
6) The reason why the tortoise won is that, the tortoise moved at a constant velocity throughout the race; the hare stopped to rest periodically.
7) Work is only said to be done when the force applied moves a distance hence, work is not done because, the object has not moved.
8) The truth about the movement of the car is that the car travels at constant velocity.
9) The mechanical advantage is defined as the ratio of load to effort. Hence the mechanical advantage = 600 Ibs/150 Ibs = 4
10) The lowest gear has the greatest mechanical advantage because it requires the least work to climb the hill.
11) A pulley helps you do work because it decreases the amount of applied force.
12) The pedals on a bicycle give a mechanical advantage by allowing you to turn the pedals a short distance to turn the larger circumference of the wheels.
13) The car is traveling with a constant velocity due to the flat line of the graph.
14) The statement Mary traveled 70 miles/hour due north is velocity.
15) speed = distance/time
time = distance/speed
time = 9 m/ 2m/s = 4.5 s
16) The force needed to push the mass to the top of the ramp can be decreased by decreasing the length of the ramp.
17) The acceleration of the car is negative when the velocity of a car reduced from 50 km/h to 35 km/h over one minute.
18) Average velocity = Distance covered in a specific direction/ time
= 25 Km due east/4 hours = 6.25 km/hr due east
19) Work done = Force × distance
Distance = Work done/Force
Distance = 96 J/16 N = 6 meters
20) The most work is done when Jeremy pushed a car up a steep hill.
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