Jack is falling down the hill at a speed of 12 m/s. If Jack has a mass of 45 kg, what is his kinetic energy?

Can we use the traditional methods of measurement? Are they reliable? If not why?

Reil [10]

Answer:

Traditional methods of measurement involve methods like measurement using the arm, foot or hand span of a particular person which can and does varies form person to person and hence can't be reliable while the standard methods have a fixed standard value which is universal and same for everybody and every place and ..

4 0

3 years ago

Distance Between Two Cars A car leaves an intersection traveling west. Its position 4 sec later is 19 ft from the intersection.

faltersainse [42]

Answer:

The answer to the question is;

The rate at which the distance between the two cars is changing is equal to 14.4 ft/sec.

Explanation:

We note that the distance traveled by each car after 4 seconds is

Car A = 19 ft in the west direction.

Car B = 26 ft in the north direction

The distance between the two cars is given by the length of the hypotenuse side of a right angled triangle with the north being the y coordinate and the west being the x coordinate.

Therefore, let the distance between the two cars be s

we have

s² = x² + y²

= (19 ft)² + (26 ft)² = 1037 ft²

s = $\sqrt{1037 ft^2}$ = 32.202 ft.

The rate of change of the distance from their location 4 seconds after they commenced their journeys is given by;

Since s² = x² + y² we have

$\frac{ds^{2} }{dt} = \frac{dx^{2} }{dt} + \frac{dy^{2} }{dt}$

→ $2s\frac{ds }{dt} = 2x\frac{dx}{dt} + 2y\frac{dy }{dt}$ which gives

$s\frac{ds }{dt} = x\frac{dx}{dt} + y\frac{dy }{dt}$

We note that the speeds of the cars were given as

Car B moving north = 12 ft/sec, which is the y direction and

Car A moving west = 8 ft/sec which is the x direction.

Therefore

$\frac{dy }{dt}$ = 12 ft/sec and

$\frac{dx}{dt}$ = 8 ft/sec

$s\frac{ds }{dt} = x\frac{dx}{dt} + y\frac{dy }{dt}$ becomes

$32.202 ft.\frac{ds }{dt} = 19 ft \times 8 \frac{ft}{sec} + 26ft\times 12\frac{ft}{sec}$ = 464 ft²/sec

$\frac{ds }{dt} = \frac{464\frac{ft^{2} }{sec} }{32.202 ft.}$ = 14.409 ft/sec ≈ 14.4 ft/sec to one place of decimal.

3 0

3 years ago

An old manuscript reveals that a landowner in the time of King Arthur held 3.00 acres of plowed land plus a livestock area of 25

iragen [17]

Answer:

(a) Total area is 14.5 roods

(b) Total area is 14674.522 square meters

Explanation:

Area occupied by land = 3 acres

1 acre = 40 perches by 4 perches = 160 square perches

3 acres = 3×160 = 480 square perches

Area occupied by livestock = 25 perches by 4 perches = 100 square perches

Total area = 480 + 100 = 580 square perches

1 rood = 4 perches by 1 perch = 4 square perches

580 square perches = 580/4 = 14.5 roods

(b) Total area = 580 square perches

1 perch = 16.5ft = 16.5/3.2808 = 5.03 meters

580 square perches × (5.03 meters/1 perch)^2 = 580 ×25.3009 square meters = 14674.522 square meters

8 0

3 years ago

A square coil, enclosing an area with sides 2.0 cm long, is wrapped with 2 500 turns of wire. A uniform magnetic field perpendic

Delvig [45]

Answer:

The induced voltage in the coil is 0.25 V.

Explanation:

It is given that,

Area of a square coil is 2 cm or 0.02 m

Number of turns in the wire is 2500

A uniform magnetic field perpendicular to its plane is turned on and increases to 0.25 T during an interval of 1.0 s.

We need to find the induced voltage in the coil. According to Faraday's law, the induced emf in the coil is given by the rate of change on magnetic flux. So,

$\epsilon=\dfrac{-d\phi}{dt}\\\\\epsilon=\dfrac{-d(NBA)}{dt}\\\\\epsilon=NA\dfrac{-dB}{dt}\\\\\epsilon=-2500\times (0.02)^2\times \dfrac{0.25}{1}\\\\\epsilon=-0.25\ V$

So, the induced voltage in the coil is 0.25 V.

3 0

3 years ago

Two objects, each with a charge of +0.15 C are separated by a distance of 3 meters.

Mrac [35]

Answer:

A . Are the masses repelling or attracting

answer:

So, positive energy densities ("masses") attract each other by gravitational interaction. This is the general idea.

B. What is the magnitude of the electrical force between the objects?

answer:

 The magnitude of the electrostatic force F between two point charges q1 and q2 is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them.

C. What would the magnitude of the force be if one of the charges was 1/3 the amount?

answer:

0.45

D. ) What would the force be if the distance between the charges was only 1 meter (with the original charges)?

answer;

Fmin=2.3×10^−28N

E: What would the force be if one of the charges was 1/3 the amount AND the distance was 1 meter?

answer;

Electrostatic force is directly related to the charge of each object. So if the charge of one object is doubled, then the force will become two times greater.

#CARRYONLEARNING:)

LOVEUALL

6 0

3 years ago