A ball of 12 kg is attached to a string of 0.8 meter spun at 4

A uniformly charged sphere has a total charge of 300uc and a radius of 8cm. Find the electric field density at A point 16cm from

s2008m [1.1K]

E = kQ 

(r + h)²

where,

k = 9 × 10^9Nm²C^-2

Q = total charge, 300uC = 300 × 10^ -6C

r = 8 × 10^ -2m

h = 16 × 10^ -2m

then,

E = 9e9 * 300e^-6 

(8e^-2 + 16e^-2)²

E = 4687500N/C

6 0

1 year ago

A football kicker kicks a ball with a mass of .42 kg. The average acceleration of the football was 14.8 m/s squared. How much fo

mrs_skeptik [129]

To find the force we use the formula,

F = ma , where m is mass and a acceleration

Using the formula,

F = ma

F = 0.42 x 14.8

F = 6.216 N / 6.22 N

Hope you liked the answer !

4 0

2 years ago

. Each valve A, B, and C, when open, releases water into a tank at its own constant rate. With all three valves open, the tank f

olasank [31]

Answer:

Time taken by A and B is 1.2 hr.

Explanation:

Given that

Time taken by tank when all(A+B+C) are open = 1 hr

Time taken by tank when A+C are open = 1.5 hr

Time taken by tank when B+C are open = 2 hr

If we treat as filling of tank is a work then

Work = time x rate

Lets take work is 1 unit

1 = 1(1/a+1/b+1/c) ---------1

1 = 1.5(1/a+1/c) ----------2

1 = 2(1/b+1/c) --------3

From equation 1 and 3

1=1(1/a+1/2)

a=2

Form equation 2

1 = 1.5(1/2+1/c)

c=6

From equation 3

1 = 2(1/b+1/6)

b=3

So time taken by

A is alone to fill tank is 2 hr

B is alone to fill tank is 3 hr

C is alone to fill tank is 6 hr

So $time\ taken\ by\ A\ and\ B =\dfrac{2\times 3}{2+3} hr$

Time taken by A and B is 1.2 hr.

7 0

2 years ago

You drop a ball at 27 feet high. How long will it take for the ball to hit the ground?

ivolga24 [154]

Ball will hit the ground after a time of 1.296 s

Explanation:

initial velocity of ball= Vi=0

g= 9.8 m/s²

height =h= 27 ft=8.23 m

using the kinematic equation

h= Vi t + 1/2 gt²

8.23=0(t) + 1/2 (9.8)t²

t²=1.6796

t=1.296 s

6 0

2 years ago

A 38-kg canoe breaks free from its dock and floats downriver at a speed of 2.2 m/s. What is the momentum of the canoe? 48.0 m/s

Brut [27]

Momentum of a body is calculated by multiplying the mass of a moving body with its velocity. When a body is at rest it has zero momentum since the velocity is also zero.
In this case the momentum of the canoe will be;
38 kg × 2.2 m/s = 83.6 kgm/s
Therefore, the correct answer is 83.6 kg m/s

3 0

2 years ago