Answer:
0.035 N
Explanation:
Parameters given:
Charge q1 = -3.31x10^(-7) C
Charge q2 = -5.7x10^(-7) C.
Distance between them, R = 22 cm = 0.22 m
Electrostatic force between to particles is given as:
F = (k* q1 * q2) / R²
F = (9 * 10^9 * -3.31 * 10^(-7) * -5.7 * 10^(-7)) / 0.22²
F = 0.035 N
Answer:
(D) The power supplied by the source decreases.
Explanation:
If additional resistors are connected in series, then the total resistance of the circuit is increased. By the Ohm’s Law, V = iR, the current decreases.
The power supplied by the source is P = i*i*R = i*(i*R). The term in the parenthesis is the voltage of the circuit and is constant. The ‘i’ outside decreases, therefore the power supplied by the source decreases.
Answer:
False
Explanation:
An object in uniform circular motion must be changing its velocity in order to move in a circular path.
In fact, remind that velocity is a vector which consists of a magnitude (the speed) and a direction.
When an object is moving in uniform circular motion, the direction of the motion is constantly changing (since the trajectory is a circle): so, this means that the velocity is also changing. However, this does not imply that the speed of the object is changing. In fact, in a uniform circular motion, the speed of the object remains constant.
<span>11.823 cm
There is a slight ambiguity with this question in that I don't know if the measurements are from the surface of the ball, or the center of the ball. I will take this question literally and as such the point light source will be 124 cm from the wall.
The key thing to remember is that ball won't be showing an effective diameter of 4 cm to the light source. Instead the shadow line is a tangent to the ball's surface. There is a right triangle where the hypotenuse is the distance from the center of the ball to the light source (42 cm), one leg of the triangle is the radius (2cm). That right triangle will define a chord that will be the effective diameter of the disk casting the shadow. The cosine of the half angle of the chord will be 2/42 = 1/21. The sine of the half angle then becomes sqrt(1-(1/21)^2) = sqrt(440/441) = 2sqrt(110) = 0.99886557. Now multiply that sine by 4 (radius of ball multiplied by 2 since it's the half angle and we want the full side of the chord) and we get an effective diameter of 3.995462279 cm.
Now we need to calculate the effective distance that circle is from the wall. It will be slightly larger than 82 cm. The exact value will be 82 + cos(half angle) * radius. So
82 + 1/21 * 2 = 82 + 2/21 = 82.0952381
Now we have the following dimensions with a circle replacing the ball in the original problem.
Distance from wall to effective circle = 82.0952381 cm
Distance from effective circle to point source = 124 - 82.0952381 = 41.9047619 cm
Effective diameter of circle = 3.995462279 cm
And because the geometry makes similar triangles, the following ratio applies.
3.995462279/41.9047619 = X/124
Now solve for X
3.995462279/41.9047619 = X/124
124*3.995462279/41.9047619 = X
495.4373226/41.9047619 = X
11.82293611 = X
The shadow cast on the wall will be a circle with a diameter of 11.823 cm</span>
Answer:
a = -8.912 m/s²
Explanation:
Given,
The initial velocity of the car, u = 28 m/s
The final velocity of the car, v = 0
The distance traveled by car, d = 88 m
The velocity displacement relation is given by the formula
v = d/t
∴ t = d/v
Substituting in the above values in the given equation
t = 88/28
= 3.142 s
The acceleration is given by the formula
a = (v-u)/t
= (0 - 28)/3.142
= -8.912 m/s²
The negative sign is that the car is decelerating.
Hence, acceleration a = -8.912 m/s²
