A ray of light travelled from water into the air an angle of incidence of 30°. Calculate;

A projectile of mass 6.8 kg kg is shot horizontally with an initial speed of 14.5 m/s from a height of 26.7 m above a flat deser

sleet_krkn [62]

Answer:

Explanation:

Given

mass of projectile $m=6.8\ kg$

initial horizontal speed $u_x=14.5\ m/s$

height $h=26.7\ m$

Considering vertical motion

velocity gained by projectile during 26.7 m motion

$v^2-u^2=2 as$

v=final velocity

u=initial velocity

a=acceleration

s=displacement

$v^2-(0)^2=2\times (9.8)\times (26.7)$

$v=\sqrt{523.32}$

$v=22.87\ m/s$

Horizontal velocity will remain same as there is no acceleration

final velocity $v_{net}=\sqrt{(v)^2+(u_x)^2}$

$v_{net}=\sqrt{733.57}=27.08\ m/s$

Initial kinetic Energy $K_i=\frac{1}{2}mu_x^2$

$K_i=\frac{1}{2}\times 6.8\times (14.5)^2=714.85\ J$

Final Kinetic Energy $K_f=\frac{1}{2}mv_{net}^2$

$K_f=\frac{1}{2}\times 6.8\times (27.08)^2$

$K_f=2493.30\ J$

Work done by all the force is equal to change in kinetic Energy of object

Work done by gravity is $W_g$

$W_g=\Delta K$

$W_g=2493.30-714.85=1778.45\ J$

8 0

3 years ago

If a small motor does 520 J of work to move a toy car 260 m in 3.0 seconds, how much power is being applied by the motor?

Lubov Fominskaja [6]

Answer:

P = 173.33 [W]

Explanation:

Power is defined as the amount of work done over a given time.

W = work = 520 [J]

t = time = 3 [s]

P = power [w]

Therefore by working relationship over time we can calculate the power.

$P =W/t\\P = 520/3\\P=173.33[W]$

4 0

3 years ago

The spacing between two closely spaced oppositely charged parallel plates is decreased. What happens to the electrostatic potent

erastovalidia [21]

<h2>Electrostatic Potential Decreases</h2>

Explanation:

If the spacing between two closely spaced oppositely charged parallel plates is decreased the electrostatic potential difference between the plates will decrease.

An electrostatic potential that is also referred to as the electric field potential or potential drop is the amount of work required to replace a unit of charge from a reference point to a specific point inside the electric field without any change in acceleration.

Therefore, if the distance will decrease between oppositely charged plates there will be more affinity to attract which will reduce the amount of work done thus decreasing the electric potential

∴ The Correct option is (b)

5 0

3 years ago

A man pushed a cabinet with a force of 200N. What is the mass of the cabinet that accelerates 4 m/s/s?

ELEN [110]

Answer:

$\boxed {\boxed {\sf 50 \ kg}}$

Explanation:

We are asked to find the mass of a cabinet, given the force and acceleration. According to Newton's Second Law of Motion, force is the product of mass and acceleration. The formula for this is:

$F= m \times a$

The force is 200 Newtons, but we should convert the units to make unit cancellation easier. 1 Newton is equal to 1 kilogram meter per second squared, so the force of 200 Newtons is 200 kilogram meters per second squared.

The mass is unknown and the acceleration is 4 meters per second per second or 4 meters per second squared.

F= 200 kg*m/s²
a= 4 m/s²

Substitute the values into the formula.

$200 \ kg *m/s^2 = m \times 4 \ m/s^2$

We are solving for the mass, m, so we must isolate the variable. It is being multiplied by 4 meters per second squared. The inverse operation of multiplication is division. Divide both sides by 4 m/s²

$\frac {200 \ kg *m/s^2}{4 \ m/s^2}= \frac{m \times 4\ m/s^2}{4 \ m/s^2}$

$\frac {200 \ kg *m/s^2}{4 \ m/s^2} =m$

The units of meters per second squared cancel.

$\frac {200 \ kg }{4 }=m$

$50 \ kg =m$

The mass of the cabinet is <u>50 kilograms.</u>

5 0

3 years ago

Lawerence kohl berg developed the theory of

Natali [406]

Explanation:

Kohlberg's theory of moral development is a theory that focuses on how children develop morality and moral reasoning. Kohlberg's theory suggests that moral development occurs in a series of six stages. The theory also suggests that moral logic is primarily focused on seeking and maintaining justice.

7 0

2 years ago