Isotopes have variable numbers of electrons.<br> a. True<br> b. False

A ball is thrown straight upward and returns to the thrower’s hand after 1.8 s in the air. A second ball is thrown at an angle o

zysi [14]

Answer:

U = 9.1 m/s

Explanation:

from the question we are given the following

time (t) = 1.8 s

angle = 23 degrees

acceleration due to gravity (g) = 9.8 m/s^{2}

let us first calculate the initial velocity (u) which too the first ball to its maximum height from the equation below

v = u + 0.5at

The final velocity (v) is zero since the ball comes to rest

The time (t) it takes to get to the maximum height would be half the time it is in the air, t = 0.5 x 1.8 = 0.9

therefore

0 = u - (0.5 x 9.8 x 0.9)

u = 7.9 m/s

for the second ball to get to the maximum height of the first ball, the vertical component of its initial velocity (U) must be the same as the initial velocity of the first ball. therefore

U sin 60 = 7.9

U = 7.9 ÷ sin 60

U = 9.1 m/s

5 0

3 years ago

Rank the six combinations of electric charges on the basis of the electric force acting on q1. Define forces pointing to the rig

g100num [7]

I have attached the image showing the 6 combination of charges

Answer:

Smallest are: q1 = +1 nc, q2 = +1 nc, q3 = +1 nc and q1 = -1 nc, q2 = -1 nc, q3 = -1nc

Third Largest: q1 = +1 nc, q2 = +1nc, q3 = -1 nc

Second Largest: q1 = +1 nc, q2 = -1 nc, q3 = +1 nc

Largest are: q1 = +1 nc, q2 = -1 nc, q3 = -1 nc and q1 = -1 nc, q2 = +1 nc, q3 = +1 nc

Explanation:

The electrostatic force between 2 charges is; F = k•q1•q2/r²

Where r is the distance between the 2 charges q1 and q2 and k is coulombs constant.

Thus;

F ∝ q1•q2/r²

The net force on the charge q1 is the sum of the forces on charge q2 and q3.

If the two charges are opposite, the force is an attractive force while if the two charges are similar, the force is a repulsive force.

Thus, if the combination has same type of charges, i.e;(+1,+1,+1) or (-1,-1,-1), the force will be very small.

So, now the order of forces from smallest to largest is;

Smallest are: q1 = +1 nc, q2 = +1 nc, q3 = +1 nc and q1 = -1 nc, q2 = -1 nc, q3 = -1nc

Third Largest: q1 = +1 nc, q2 = +1nc, q3 = -1 nc

Second Largest: q1 = +1 nc, q2 = -1 nc, q3 = +1 nc

Largest are: q1 = +1 nc, q2 = -1 nc, q3 = -1 nc and q1 = -1 nc, q2 = +1 nc, q3 = +1 nc

3 0

3 years ago

A 3.9 kg block is pushed along a horizontal floor by a force of magnitude 30 N at a downward angle θ = 40°. The coefficient of k

Luba_88 [7]

Answer:

The frictional force $F_{fri} =$ 6.446 N

The acceleration of the block a = 6.04 $\frac{m}{s^{2} }$

Explanation:

Mass of the block = 3.9 kg

$\theta = 40$ °

$\mu$ = 0.22

(a). The frictional force is given by

$F_{fri} = \mu R_{N}$

$R_{N} = mg \cos \theta$

$R_{N} =$ 3.9 × 9.81 × $\cos 40$

$R_{N} =$ 29.3 N

Therefore the frictional force

$F_{fri} =$ 0.22 × 29.3

$F_{fri} =$ 6.446 N

(b). Block acceleration is given by

$F_{net} = F - F_{fri}$

F = 30 N

$F_{fri}$ = 6.446 N

$F_{net}$ = 30 - 6.446

$F_{net}$ = 23.554 N

The net force acting on the block is given by

$F_{net} = ma$

23.554 = 3.9 × a

a = 6.04 $\frac{m}{s^{2} }$

This is the acceleration of the block.

8 0

3 years ago

How are mass and inertia related?

aleksandr82 [10.1K]

The greater the mass the greater is inertia.

7 0

3 years ago

An electric light is plugged into a 120-V outlet. If the current in the bulb is 0.50 A, how much electrical energy does the bulb

ioda

Answer:

= 54,000 Joules or 54 kJ

Explanation:

Electrical energy is given by the formula;

E = VIt; where V is the potential difference in volts, I is the current and t is the time in seconds.

Therefore;

Electrical energy = 120 V × 0.50 A × 15 ×60 seconds

= 54,000 Joules

Thus; the electrical energy is 54,000 joules or 54 kJ

7 0

3 years ago

Isotopes have variable numbers of electrons. a. True b. False