Answer:
the velocity in all the cases will be same.
Explanation:
given,
girl throws a stone from the bridge
air is friction less
we have to find from the given cases in which case the velocity of stone will be greatest.
According to Work energy theorem work done by the sum of all the force is equal to kinetic energy.
As the air is frictionless hence the speed depend upon the height from which the stone is thrown.
height in all the cases is same.
so, the velocity in all the cases will be same.
Answer:
F = 39.2 N
Explanation:
Since, the object is in uniform motion. Therefore, the frictional force on object will be:
Frictional Force = μk N = μk mg
where,
μk = coefficient of kinetic friction = 0.2
m = mass of crate = 10 kg
g = 9.8 m/s²
Therefore,
Frictional Force = (0.2)(10 kg)(9.8 m/s²)
Frictional Force = 19.6 N
The horizontal component of force must be equal to this frictional force to continue the uniform motion:
F Sin 30° = 19.6 N
F = 19.6 N/Sin 30°
<u>F = 39.2 N</u>
<u>Answer:
</u>
Distance traveled = 70 meters
Displacement = 36.06 meters
<u>Explanation:
</u>
Let north be positive Y and east be positive X
10 meters north, displacement = 10 j meters
20 meters west, displacement = -20 i meters
40 meters south, displacement = -40 j meters
Total displacement = (10 j - 20 i – 40 j) meters = (- 20 i - 30 j) meters
Magnitude of displacement = 
Distance traveled = 10+20+40 = 70 meters
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