Answer:
A. 2.83 m/s
B. 39.55 degrees north of east
Explanation:
The velocity of the ball relative to the ground is the sum vectors of velocity of the ball relative to Mia and the velocity of Mia relative to the ground
If we take north east as positive direction then
Velocity vector of the ball relative to Mia is
Velocity of Mia relative to gorund is
<0, 5.3>
So velocity of the ball relative to the ground is
<1.8, -3.12> + <0, 5.3> = <1.8, 2.18>
Its magnitude is:
m/s
Its direction is
north of east
Answer:
Explanation:
The bulldozer is moving the rocks as one system, the weigth for the complete system is:
From newton´s second law the acceleration can be related to the force by:
on the middle rock we have the force F12 from the first to the middle rock on the direction of movement and F32 from the las rock to the middle rock on the opposite direction of movement.
For the last rock to accelerate at the same rate it must be subjected to a force:
This equals the force F32 on the opposite direction. the resultant force on the middle rock to mantain this acceleration should be:
The sum of all the forces applied to the middle rock is:
Solving for F12:
Answer:
the correct one is C
Explanation:
For this exercise we must use the work definition
W = F. s
Where the bold characters indicate vectors and the point is the scalar producer
W = F s cos θ
Where θ is the angles between force and displacement.
Let us support this in our case. The cable creates an upward tension and with the elevator going down the angle between them is 180º so the work of the cable on the elevator is negative.
The evade has a downward force, its weight so the force goes down and the displacement goes down, as both are in the same direction the work is positive
When examining the statements the correct one is C
Answer:
a) ΔV = 20 V
, b) Q = 35.4 10⁻⁹ C, c) C = 1.77 10⁻⁹ F
Explanation:
a) The electric potential is
ΔV = E x
ΔV = 4.0 10⁵ 50 10⁻⁶
ΔV = 20 V
c) The capacity of a capacitor is
C = ε₀ A / d
The area of a square plate is
A = L²
A = 0.10²
A = 0.01 m²
L = 50mm = 50 10⁻⁶ m
Let's calculate
C = 8.85 10⁻¹² 0.01 /50 10⁻⁶
C = 1.77 10⁻⁹ F
b) the charge is
Q = C ΔV
Q = 1.77 10⁻⁹ 20
Q = 35.4 10⁻⁹ C
Answer:
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Explanation: