This is so easy freezing and boiling, are you in 4th?
Answer:
σ = ±708 nC/m²
Q = ±177 nC
Explanation:
given data
Side of copper plate L = 50 cm
Electric field, E = 80 kN/C
solution
we get here Charge density,σ that is express as
σ = E x ε₀ ....................1
here ε₀ is Permittivity of free space that is 8.85 x 10⁻¹² C²/Nm²
so put value in eq1we get
σ = 80 x 10³ x 8.85 x 10⁻¹²
σ = 708 x 10⁻⁹ C/m²
σ = 708 nC/m²
and
now we get here total change on each faces
Q = σ A ...............2
Q = 708 x 10⁻⁹ x (0.50)²
Q = 177 nC
Answer:
(A) 374.4 J
(B) -332.8 J
(C) 0 J
(D) 41.6 J
(E) 351.8 J
Explanation:
weight of carton (w) = 128 N
angle of inclination (θ) = 30 degrees
force (f) = 72 N
distance (s) = 5.2 m
(A) calculate the work done by the rope
- work done = force x distance x cos θ
- since the rope is parallel to the ramp the angle between the rope and
the ramp θ will be 0
work done = 72 x 5.2 x cos 0
work done by the rope = 374.4 J
(B) calculate the work done by gravity
- the work done by gravity = weight of carton x distance x cos θ
- The weight of the carton = force exerted by the mass of the carton = m x g
- the angle between the force exerted by the weight of the carton and the ramp is 120 degrees.
work done by gravity = 128 x 5.2 x cos 120
work done by gravity = -332.8 J
(C) find the work done by the normal force acting on the ramp
- work done by the normal force = force x distance x cos θ
- the angle between the normal force and the ramp is 90 degrees
work done by the normal force = Fn x distance x cos θ
work done by the normal force = Fn x 5.2 x cos 90
work done by the normal force = Fn x 5.2 x 0
work done by the normal force = 0 J
(D) what is the net work done ?
- The net work done is the addition of the work done by the rope, gravitational force and the normal force
net work done = 374.4 - 332.8 + 0 = 41.6 J
(E) what is the work done by the rope when it is inclined at 50 degrees to the horizontal
- work done by the rope= force x distance x cos θ
- the angle of inclination will be 50 - 30 = 20 degrees, this is because the ramp is inclined at 30 degrees to the horizontal and the rope is inclined at 50 degrees to the horizontal and it is the angle of inclination of the rope with respect to the ramp we require to get the work done by the rope in pulling the carton on the ramp
work done = 72 x 5.2 x cos 20
work done = 351.8 J
Answer:
The rocket above the ground is in 44 sec.
Explanation:
Given that,
Initial velocity = 92 m/s
Acceleration = 4 m/s²
Altitude = 1200 m
Suppose, How long was the rocket above the ground?
We need to calculate the time
Using equation of motion

Put the value into the formula



We need to calculate the velocity
Using equation of motion

Put the value into the formula


When the rocket hits the ground,
Then, h'=0
We need to calculate the time
Using equation of motion

Put the value into the formula



When the rocket is in the air it is the sum of the time when it reaches 1000 m and the time when it hits the ground
So, the total time will be


Hence, The rocket above the ground is in 44 sec.
Answer:

Explanation:
From Newton's 2nd Law, we have
. Using this, we can find the acceleration of the object:
.
Now that we've found the block's acceleration, we can use the following kinematics equation to find its final velocity after 2 seconds:

*Assumption: The block is initially at rest and has a initial velocity of zero. Otherwise, the question is unsolvable.