What is one benefit of lifelong physical activity?

You are driving a 2400.0-kg car at a constant speed of 14.0 m/s along a wet, but straight, level road. As you approach an inters

olya-2409 [2.1K]

Answer:0.43

Explanation:

Given

mass of car $m=2400 kg$

Speed of car $u=14 m/s$

Distance traveled before coming to halt $s=23.2 m$

Let $\mu$ the coefficient of friction

Maximum deceleration road can provide during motion is

$a=\mu g$

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

$0-14^2=2\cdot (-\mu g)\cdot 23.2$

$\mu =\frac{196}{454.72}$

$\mu =0.431$

7 0

3 years ago

What are plane mirrors ?

forsale [732]

Explanation:

Mirrors consist of reflecting surfaces that reflect light.

Reflection is a phenomenon of light wave (but also of other types of waves) in which a ray of light hits a surface, and then it bounces back into the original medium at a certain angle.

The direction of the reflected ray is determined by the law of reflection:

The incident ray, the reflected ray and the normal to the surface all lie in the same plane
The angle of reflection is equal to the angle of incidence (where both angles are measured between the ray and the normal to the surface)

A plane mirror is a type of mirror consisting of a straight surface. As a result, light incident perpendicular to the surface is reflected back exactly in the opposite direction.

The image formed by a plane mirror is:

- The same size as the object

- Virtual (it is located behind the mirror)

- Laterally inverted

- Upright

3 0

3 years ago

Alpha particles consist of two protons and two neutrons bound together into a particle identical to a helium nucleus. They have

vovangra [49]

I'm not so sure if it is 5 clicks or 0 clicks

6 0

3 years ago

Read 2 more answers

You test a moon buggy on Earth. When the buggy hits a bump, it oscillates up and down on its springs with a period of 4 seconds.

Blizzard [7]

Answer:

Remains same

Explanation:

$T$ = Time period of oscillation

$m$ = mass

$k$ = spring constant

Time period of oscillation is given as

$T = 2\pi \sqrt{\frac{m}{k} }$

we know that as we move from earth to moon, the value of spring constant "k" and mass "m" remains unchanged because they do not depend on the acceleration due to gravity.

Time period depends on spring constant inversely and directly on the mass.

hence the time period remains the same.

3 0

3 years ago

A car of mass 1600 kg traveling at 27.0 m/s is at the foot of a hill that rises vertically 135 m after travelling a distance of

Zarrin [17]

Answer:

Neglecting any frictional losses, the average power delivered by the car's engine is 10565 W

Explanation:

The energy conservation law indicates that the energy must be the same at the bottom of the hill and at the top of the hill.

The energy at the bottom is only the Kinect energy (K_1) of the car in motion, but in the top, the energy is the sum of its Kinect energy (K_2), potential energy (P) and the work (W) done by the engine.

$K_1 = K_2 + P + W$

then, the work done by the engine is:

$W = K_1 - K_2 - P$

The formulas for the Kinetic and potential energy are:

$K=\frac{1}{2}mV^2\\P=mgh$

where, m is the mass of the car, V the velocity, g the gravity and h is the elevation of the hill.

Using the formulas:

$W=\frac{1}{2}mV_1^2-\frac{1}{2}mV_2^2-mgh$

Replacing the values:

$W=\frac{1}{2}(1600Kg)(27m/s)^2-\frac{1}{2}(1600Kg)(14m/s)^2-(1600Kg)(9.8m/s^2)(135m)\\W=-1690400 J$

The negative of this value indicates the direction of the work done, but for the problem, you only care about the magnitude, so the power is W=1690400 J. Now, the power is equal to work/time so you need to find the time the car took to get to the top of the hill.

The average speed of the car is (27+14)/2=20m/s, and t=d/v so the time is:

$t=\frac{3200m}{20m/s}=160s$

the power delivered by the car's engine was:

$power=\frac{work}{time}=\frac{1690400J}{160s}=10565W$

8 0

3 years ago