Answer:
35 J
Explanation:
The man is holding the box: this means that he is applying a force vertically upward, to balance the weight of the box (which pushes downward).
Therefore, we can ignore the horizontal displacement of the man, because the force applied (vertically upward) is perpendicular to that displacement (horizontal), so the work done for that is zero.
So, only the vertical motion contributes to the work. The work done by the man is equal to the gain in gravitational potential energy of the box, so:

where
is the weight of the box
is the vertical displacement
Substituting, we find

Answer:
a) One
Explanation:
In a uniform circular motion there must be a force acting to keep it in the circular track. This force can either be centripetal or a centrifugal force.
According to the Newton's first law of motion a particle continues to be in state of rest or in uniform motion until acted upon by an external force.
Here the term uniform motion need to be understood which refers to the uniform velocity of the particle in accordance to the vector laws.
Answer:
F = 316.22 N
Explanation:
Given that,
The wind blows a jay bird south with a force of 300 Newtons.
The jay bird flies north, against the wind, with a force of 100 newtons.
Both the forces are acting perpendicular to each other. The net force is given by the resultant of forces as follows :

Hence, the net force on the jay bird is 316.22 N.
Answer:
1027.2 m
Explanation:
t = Time taken
u = Initial velocity
v = Final velocity
s = Displacement
a = Acceleration due to gravity = 32.2 ft/s


The height the tomato would fall is 450+577.2 = 1027.2 m
Answer
given,
net charge = +2.00 μC
we know,
1 coulomb charge = 6.28 x 10¹⁸electrons
1 micro coulomb charge = 6.28 x 10¹⁸ x 10⁻⁶ electron
= 6.28 x 10¹² electrons
2.00 μC = 2 x 6.28 x 10¹² electrons
= 1.256 x 10¹³ electrons
since net charge is positive.
The number of protons should be 1.256 x 10¹³ more than electrons.
hence, +2.00 μC have 1.256 x 10¹³ more protons than electrons.