Please Help!! When do ionic bonds occur?

A train travels 69 kilometers in 3 hours, and then 51 kilometers in 2 hours. What is its average speed? Your Answer: Question 14

tamaranim1 [39]

Average speed = (total distance covered) / (time to cover the distance)

Total distance = 69 km + 51 km = 120 km

Total time = 3 hrs + 2 hrs = 5 hrs

Average speed = (120 km) / (5 hrs) = 24 km/hr

5 0

3 years ago

A 8.0\,\text {kg}8.0kg8, point, 0, start text, k, g, end text box is released from rest at a height y_0 =0.25\,\text my 0 =0.2

Ratling [72]

Answer:

μ = 0.125

Explanation:

To solve this problem, which is generally asked for the coefficient of friction, we will use the conservation of energy.

Let's start working on the ramp

starting point. Highest point of the ramp

Em₀ = U = m h y

final point. Lower part of the ramp, before entering the rough surface

$Em_{f}$ = K = ½ m v²

as they indicate that there is no friction on the ramp

Em₀ = Em_{f}

m g y = ½ m v²

v = $\sqrt{2gy}$

we calculate

v = √(2 9.8 0.25)

v = 2.21 m / s

in the rough part we use the relationship between work and kinetic energy

W = ΔK = K_{f} -K₀

as it stops the final kinetic energy is zero

W = -K₀

The work is done by the friction force, which opposes the movement

W = - fr x

friction force has the expression

fr = μ N

let's write Newton's second law for the vertical axis

N-W = 0

N = W = m g

we substitute

-μ m g x = - ½ m v²

μ = $\frac{v^{2} }{2 g x}$

Let's calculate

μ = $\frac{2.21^{2}}{2\ 9.8\ 2.0}$

μ = 0.125

4 0

3 years ago

A ship can carry more load than aeroplane of same size. why?

stepladder [879]

Answer:

density of water is much greater than density of air

Explanation:

when body is in fluid it carries weight which is always equal to upthrust

upthrust is given as

upthrust= density of fluid ×strength of gravitational field g × volume of body in fluid

as volume of ship and aeroplane is same and strength of gravitational field or acceleration due to gravity is same hence upthrust depens upon density of fluid .

density of air is about 1.2 kg/m^3 and density of water is 1000kg/m^3 hence ship carries more load

8 0

4 years ago

Why Ice Is Slippery?

goldfiish [28.3K]

Because ice is less dense than liquid water,
its melting point is lowered under high pressures.

A long standing theory says that this is what causes ice to be slippery:

As you step on it, the pressure of your weight causes the top layer to my into water.

3 0

3 years ago

Read 2 more answers

A brick is dropped (zero initial speed) from the roof of a building. The brick strikes the ground in 1.90 s. You may ignore air

kozerog [31]

Answer:

h=17m

v=18.6 m/s

Explanation: The question can be solved by applying kinematic equations of motion

Data

u=0

a=g