Answer:
Explanation:
a) The magnitude of the net force on the student = 0 N since the student is standing still on level ground and upward reaction force = downward force.
b) the magnitude of the contact force on the student by the backpack = 80 N since the student was backing the backpack
c) the magnitude of the contact force o the student by the ground = 550 N + 80 N = 630 N reactional force on the student
Answer: 
Explanation:
We are told both planets describe a circular orbit around the star S. So, let's approach this problem begining with the angular velocity 
of the planet P1 with a period 
:
(1)
Where:
is the velocity of planet P1
is the radius of the orbit of planet P1
Finding :
(2)
(3)
(4)
On the other hand, we know the gravitational force 
between the star S with mass 
and the planet P1 with mass 
is:
(5)
Where 
is the Gravitational Constant and its value is 
In addition, the centripetal force 
exerted on the planet is:
(6)
Assuming this system is in equilibrium:
(7)
Substituting (5) and (6) in (7):
(8)
Finding :
(9)
(10)
Finally:
(11) This is the mass of the star S
The minimum initial speed of the dart so that the combination makes a complete circular loop after the collision is 58.5 m/s.
<h3>Minimum speed for the object not fall out of the circle</h3>
The minimum speed if given by tension in the wire;
T + mg = ma
T + mg = m(v²)/R
tension must be zero for the object not fall
0 + mg = mv²/R
v = √(Rg)
<h3>Final speed of the two mass after collision</h3>
Use the principle of conservation of energy
K.Ef = K.Ei + P.E
¹/₂mvf² = ¹/₂mv² + mg(2R)
¹/₂vf² = ¹/₂v² + g(2R)
¹/₂vf² = ¹/₂(Rg) + g(2R)
vf² = Rg + 4Rg
vf² = 5Rg
vf = √(5Rg)
vf = √(5 x 2.8 x 9.8)
vf = 11.7 m/s
<h3>Initial speed of the dart</h3>
Apply principle of conservation of linear momentum for inelastic collision;
5v = vf(20 + 5)
5v = 11.7(25)
5v = 292.5
v = 58.5 m/s
Learn more about linear momentum here: brainly.com/question/7538238
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m = mass held by mr. Z above his head = 200 kg
g = acceleration due to gravity = 9.8 m/s²
F = force applied by mr. Z to hold the mass
Using equilibrium of force , force equation is given as
F = mg
F = (200) (9.8)
F = 1960 N
Since the mass is not moved,
d = displacement of the mass = 0 m
we know that , work done is given as
W = F d
inserting the values
W = (1960) (0)
W = 0 J
Answer:
A
Explanation:
As an object gets hotter the faster the molecules go
