Answer:
Well I'm going to go with A.
Explanation:
As per the question the mass of the boy is 40 kg.
The boy sits on a chair.
We are asked to calculate the force exerted by the boy on the chair at sea level.
The force exerted by boy on the chair while sitting on it is nothing else except the force of gravity of earth i.e the weight of the body .The direction of that force is vertically downward.
At sea level the acceleration due to gravity g = 9.8 m/s^2
Therefore, the weight of the boy [m is the mass of the body]
we have m = 40 kg.
Therefore, w = 40 kg ×9.8 m/s^2
=392 N kg m/s^2
= 392 N
392 is not an option but I'm guessing you can round down 2 .to option A. 390...?
Answer:
91.5 m/s
Explanation:
m = mass of clay = 12 g = 0.012 kg
M = mass of wooden block = 100 g = 0.1 kg
d = distance traveled by the combination before coming to rest = 7.5 m
μ = Coefficient of friction = 0.65
V = speed of the combination of clay and lock just after collision
V' = final speed of the combination after coming to rest = 0 m/s
acceleration caused due to friction is given as
a = - μ g
a = - (0.65) (9.8)
a = - 6.37 m/s²
Using the kinematics equation
V'² = V² + 2 a d
0² = V² + 2(- 6.37) (7.5)
V = 9.8 m/s²
v = speed of clay just before collision
Using conservation of momentum
m v = (m + M) V
(0.012) v = (0.012 + 0.100) (9.8)
v = 91.5 m/s
Answer:
4.05 m/s
Explanation:
We shall represent the different velocity in vector form
Newton runs due north at 3.90 m/s, with respect to standing Daniel .
V_n = 3.9 j
Let Pauli runs with respect to standing Daniel with velocity X .
Then relative velocity of Newton with respect to running Pauli will be
3.9 j - X
Give that
relative velocity of Newton with respect to running Pauli = 1.1 i ( 1.1 due east )
So
3.9 j - X = 1.1 i
X = -1.1 i + 3.9 j .
Magnitude of X
X² = 1.1 ² + 3.9²
X = 4.05 m/s
So Pauli runs with respect to standing Daniel with velocity 4.05 m /s .
Direction will be , west of north at angle θ ,
Tan θ = 1.1 / 3.9
Answer:
Explanation:
Ptolemy and Copernicus have presented different model in front of us.
As per Ptolemy, Earth is the center of the universe and all other planets and celestial bodies such as moon or Sun revolve around it. So as per his theory he would say that the celestial would rotate in west side due to which Sun would appear in eastern horizon.
But Copernicus theory is a contradiction of Ptolemy's work. As per him, Sun is the center of the universe and all other planets revolve around it. For the Sun rise event, he would have said the Earth rotates at east side and Sun appears.
Answer:
7.28×10⁻⁵ T
Explanation:
Applying,
F = BILsin∅............. Equation 1
Where F = magnetic force, B = earth's magnetic field, I = current flowing through the wire, L = Length of the wire, ∅ = angle between the field and the wire.
make B the subject of the equation
B = F/ILsin∅.................. Equation 2
From the question,
Given: F = 0.16 N, I = 68 A, L = 34 m, ∅ = 72°
Substitute these values into equation 2
B = 0.16/(68×34×sin72°)
B = 0.16/(68×34×0.95)
B = 0.16/2196.4
B = 7.28×10⁻⁵ T