As speed (velocity) increases, potential energy increases true or false

What is the average power supplied by a 60.0 kg secretary running up a 4.0 m tall flight of stairs in 4.2 s?

Alchen [17]

A 60.0 kg secretary running up a 4.0 m tall flight of stairs in 4.2 s has an average power of 560 W (Option b).

<h3>What is power?</h3>

Power is the work done over a period of time.

A secretary with a mass (m) of 60.0 kg runs up a 4.0 m (d) tall flight of stairs. Given gravity (g) is 9.81 m/s², the work (W) done is:

W = m × g × d = 60.0 kg × 9.81 m/s² × 4.0 m = 2.35 × 10³ J

They do 2.4 × 10³ J of work in 4.2 s (t). The average power (P) is:

P = W / t = 2.35 × 10³ J / 4.2 s = 560 W

A 60.0 kg secretary running up a 4.0 m tall flight of stairs in 4.2 s has an average power of 560 W (Option b).

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8 0

2 years ago

Before collecting a specimen of urine or feces, the nursing assistant asks the nurse or consults the lab for?

bulgar [2K]

Before collecting a specimen of urine or feces, the nursing assistant asks the nurse or consults the lab for which storage and delivery method to use.

There are different tests that need to be performed on a urine or feces specimen. It depends on the patients that which test would be asked for him to be done.

The storage and delivery methods for urine and feces in the case of different tests has to be consulted by the nurse or consultant.

Incase of an emergency test, whose results are immediately required the method of delivery is a fast mode one. For patients that have a mild disease or are not at risk, other reliable methods can be used. Each specimen should be properly labeled for proper checking.

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8 0

2 years ago

I will mark brainliest

Travka [436]

Answer:

Explanation:

I hope this helped

5 0

3 years ago

A horizontal force of magnitude 31.3 N pushes a block of mass 4.30 kg across a floor where the coefficient of kinetic friction i

Ostrovityanka [42]

Answer:

$W_{F} = +119.6 J$ : Work done by horizontal force

$W_{Ff} = -96.42 J$ : Work done by friction force

$W_{n} = 23.18 J$ : Net work

Explanation:

Work theory

Work is the product of a force applied to a body and the displacement of the body in the direction of this force.

Thus. The work is equal to the product of the force by the distance (d) and by the cosine of the angle ( α) that exists between the direction of the force (F) and the direction that travels the point or the object that moves:

W= F*d*cosα Formula (1)

The work is positive (W+) if the force goes in the same direction of movement.

The work is negative (W-)if the force goes in the opposite direction to the movement

Net work (Wn)

Net work is defined as the sum of the work done from an initial place to an end point of the trajectory, for each of the individual forces to which the system is subjected.

Problem development

We determine the forces that perform work:

in formula (1 )we observe that the forces that perform work are the forces parallel to displacement. that is α = 0.

For this case they are the horizontal force (F) and the frictional force (Ff)

F=31.3 N : Horizontal force

Ff=μk*N , μk:coefficient of kinetic friction , N : Normal force

N=W

W: block weight W= m*g, m: block mass , g: acceleration due to gravity

W= 4.30 kg* 9.8 m/s² = 42.14 N

Ff= 0.599*42.14 N= 25.24 N : Frictional force

Calculating of the Net work (Wn)

$W_{n} = W_{F} +W_{Ff}$

$W_{F} = 31.3N*3.82 m$

$W_{F} = 119.6 N*m$

$W_{F} = +119.6 J$

$W_{Ff} = -25.24N*3.82m$

$W_{Ff} = -96.42 N* m$

$W_{Ff} = -96.42 J$

$W_{n} = W_{F} +W_{Ff}$

$W_{n} = ( 119.6 -96.42) N*m$

$W_{n} = 23.18 N*m$

$W_{n} = 23.18 J$

8 0

3 years ago

A 76g ball is attached to a string that is 1.5m long. It is spun so that it completes two full rotations every second. What is t

Marat540 [252]

The centripetal acceleration = 236.63 m/s²

The force = 17.98 N

<h3>Further explanation</h3>

Given

mass = 76 g = 0.076 kg

r = 1.5 m

f = 2 rps = 2 rotation per second

Required

The centripetal acceleration

The Force tension

Solution

Centripetal force is a force acting on objects that move in a circle in the direction toward the center of the circle

$\large {\boxed {\bold {F = \frac {mv ^ 2} {R}}}$

F = centripetal force, N

m = mass, Kg

v = linear velocity, m / s

r = radius, m

The speed that is in the direction of the circle is called linear velocity

Can be formulated:

$\tt \displaysyle v = 2 \pi.r.f$

r = circle radius

f = rotation per second (RPS)

The linear velocity : 2 x 3.14 x 1.5 x 2 =18.84 m/s

The centripetal acceleration : ac = v²/R = 236.63 m/s²

The force : F = m x ac = 0.076 x 236.63 = 17.98 N

4 0

3 years ago