Answer:
Average speed = distance/time
From 1 to 9 seconds:
Distance covered = 1 - 0.2 = 0.8 km
Time = 9 - 1 = 8 sec
Average speed = 0.8 km / 8 sec
Average speed = 0.1 km/s .
The average speed for the whole test is 1.6 km / 20 sec = 0.08 km/sec. A graph of speed vs time would average out as a horizontal line at 0.08 km/sec from 1 sec to 21 sec. The area under it would be (0.08 km/s) x (20 sec) = 1.6 km.
Surprise surprise ! The area under a speed/time graph is the distance covered during that time !
In closing, I want to express my gratitude for the gracious bounty of 3 points with which I have been showered. Moreover, the green breadcrust and tepid cloudy water have also been refreshing.
Explanation:
#82
here we know that
acceleration = 2 m/s/s
time = 5 s
initial speed = 4 m/s
now we can use kinematics to find the final speed
So correct answer will be option D)
#83
here we know that
acceleration = 3 m/s/s
time = 4 s
initial speed = 5 m/s
now we can use kinematics to find the final speed
So correct answer will be option C)
#84
here we know that
acceleration = 7 m/s/s
time = 3 s
initial speed = 8 m/s
now we can use kinematics to find the final speed
So correct answer will be option C)
Answer:
The correct option is;
The sports car, because it has less mass and therefore less inertia
Explanation:
Newton's first law of motion states that an object will continue in its state of rest or uniform motion in a straight line unless acted on by a force. The property exhibited by the object is known as inertia
Newton's second law states that force is directly proportional to the rate of change of momentum produced
The rate of change of momentum of an object is directly proportional to the resultant force applied and is in the direction of the resultant force. The resultant force is equal to the rate of change of momentum.
Therefore, we have;
F = m·dv/dt = m×a
Given that the force required to move an object is directly proportional to its mass therefore, the inertia or the object resistance that requires a force to bring change is directly proportional to the mass of the object.
The mass of a sports car being considered lesser than the mass of the minivan will require less force to push and therefore has less inertia.
This question is incomplete, the complete question is;
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A constant force F = 6i+8j-6k moves an object along a straight line from point (6, 0, -10) to point (-6, 7, 2).
Find the work done if the distance is measured in meters and the magnitude of the force is measured in newtons.
Answer:
the work done is -88 J
Explanation:
Given the data in the question;
we know that;
Work done = F × S
where constant force F = ( 6i + 8j - 6k )
S = ( -6i + 7j + 2k ) - ( 6i + 0j - 10k )
S = ( (-6i - 6i) + (7j - 0j) + ( 2k - ( -10k) ) )
S = ( -12I + 7j + 12k )
so
Work force = ( 6i + 8j - 6k ) × ( -12I + 7j + 12k )
Work force = ( 6 × -12 ) + ( 8 × 7 ) + ( -6 × 12 )
Work force = -72 + 56 - 72
Work force = -88 J
Therefore, the work done is -88 J
E is correct because net force in the forward direction is greater
