All categories

3 years ago

HELP PLS !!!!!!!!!!!!!!!!!!!!]

Physics

1 answer:

irina [24]3 years ago

6 0

Answer:

0.25

Explanation:

According to newtons law of motion

\sum F_x = ma

F_f = ma

nR = ma

nmg = ma

ng = a

n = a/g

g is the acceleration due to gravity

Given

a = 2.42m/s²

g = 9.8m/s²

Substitute into the formula;

n = 2.42/9.8

n = 0.25

Hence the coefficient of kinetic friction is 0.25

You might be interested in

A packet is dropped from a stationary helicopter, hovering at a height 'h' from the ground level, reaches the ground in 12s. Cal

Ksju [112]

Use kinematic equations to solve:

1) yf = yo + vo*t + 1/2at²

yf = final height
yo = initial height
vo = initial velocity
a = acceleration
t = time

yf - yo = vo*t + 1/2at²

yf - yo = h

vo = 0

Thus,

h = 1/2at²

h = 1/2(9.8)(12)² = 705.6 m

2) vf = vo + at

vo = 0

Thus,

vf = at

vf = (9.8)(12) = 117.6 m/s

4 0

4 years ago

What is the frequency of light when the energy for a mole of photons is 1. 55 × 1013 j?.

ValentinkaMS [17]

The frequency of light is 3.88 x 10^22Hz.

What is electromagnetic radiation?

The electromagnetic spectrum is the area where the electromagnetic radiation that we see as light, or visible light, is found. Visible light usually has wavelengths between 400 and 700 nanometers (nm) or frequencies between 750 and 420 terahertz, which are between the longer wavelengths of infrared and ultraviolet (with shorter wavelengths).

E = 1.55 x10^13 J/ mol

E = hv

v = 1.55 x 10^13/1mol x 1mol/6.023 x )/6.626 x

velocity = 3.88x10^22 s-1

since 1 Hz = 1/ s = 1

velocity =3.88x 10^22 Hz

To learn more about Light the link is given below:

brainly.com/question/1555553

#SPJ4

3 0

2 years ago

a stone is vertically thrown upward with the velocity of 72km/hr find the maximum height reached the height

erik [133]

Answer:

y = 20.38 [m]

Explanation:

In order to solve these problems, we must use the following kinematics equation.

$v_{f} ^{2} =v_{i} ^{2}-(2*g*y)$

where:

Vf = final velocity = 0

Vi = initial velocity = 72 [km/h]

g = gravity acceleration = 9.81 [m/s^2]

y = vertical elevation [m]

We need to convert [km/h] to [m/s]

$72[\frac{km}{h}]*[\frac{1h}{3600s}]*[\frac{1000m}{1km} ] = 20 [m/s]$

Note: the negative sign of the equation means that the acceleration acts in the opposite direction to the movement of the body. And the final speed is zero, because when the body reaches the maximum height, the Stone does not move its speed has been reduced to its entirety.

0 = (20)^2 - (2*9.81*y)

20^2 = 2*9.81*y

y = 20.38 [m]

3 0

3 years ago

Van traveling at 30 km/h slows to 20 km/h in 3 seconds. What is the acceleration of the van?

adell [148]

Yes, you need to convert unless the question specifically requires km/h.

7 0

3 years ago

A 100-kg box is a rest on the floor. The coefficient of static friction between the box and the floor is 0.40, while the coeffic

pantera1 [17]

Answer:

The normal force acting on the block is 980 N.

Explanation:

Mass of box = 100 kg

Coefficient of static friction = 0.40

Coefficient of kinetic friction = 0.20

We need to calculate the normal force

We know that,

When the object is placed on the flat surface then the normal force is equal to the weight of the object.

So. The normal force = mass x acceleration due to gravity

$N=mg$

Where, N = Normal force

m = mass of object

g = acceleration due to gravity

$N=100\times9.8$

$N=980\ N$

Hence, The normal force acting on the block is 980 N.

6 0

3 years ago