1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
julia-pushkina [17]
2 years ago
14

. While a person lifts a book of mass 2 kg from the floor to a tabletop, 1.5 m above the floor, how much work does the the perso

n do on the book? How much work does gravity do on the boo
Physics
2 answers:
viktelen [127]2 years ago
5 0

Answer:

a) 29.4 J

b) - 29.4 J

Explanation:

Given:

Mass of the book, m = 2 kg

Height above the floor, h = 1.5 m

Now,

the work done by the person will be = Force applied on the book × displacement of the book

thus,

Work done by the person = mg × h

where, g is the acceleration due to gravity

thus, on substituting the values, we get

Work done by the person = 2 × 9.8 × 1.5 = 29.4 J

now,

for the force applied by the gravitational pull (downwards) the displacement is in opposite direction (upwards) to the force of the gravity.

Thus,

work done by the gravity will be negative

therefore, the work done by the gravity = - mg × h

or

work done by the gravity = - 29.4 J

photoshop1234 [79]2 years ago
4 0

Answer:

29.4 J  -29.4 J

Explanation:

The work done by the person on the book is given by =mgh

where m =mass

          g= acceleration due to gravity

          h=height

Here m=2 kg given g=9.8 kg m/sec^2 h=1.5 meter

So work done by the person =2×9.8×1.5=29.4 J

As the gravitational force work downward and person lift the book upward so work done by gravity = -mgh = -2×9.8×1.5=  -29.4 J  

You might be interested in
Which FBD would represent a car moving right with a motor force of 250 N, and force of friction of 750N, a weight of 8500N and a
babymother [125]

Answer:

Option C

Explanation:

Given that

Motor force is 250 N

Force of friction is 750 N

Weight is 8500 N

And, the normal force is 8500 N

Now based on the above information

Here length of the rector shows the relative magnitude forward force i.e. 250 N i..e lower than the frictional force i.e. backward and weight i.e. 8500 would be equivalent to the normal force

8 0
2 years ago
AYUDAAA PORFAVOR
Sholpan [36]

Queremos crear un diagrama general para calcular el área de un triangulo.

Este será algo como:

  1. Definir variables
  2. Pedirle al usuario que introduzca los valores deseados (de las variables).
  3. Leer los valores deseados y asignarlo a la variable correspondiente.
  4. Realizar la operación para calcular el área.
  5. Mostrar en pantalla el resultado.

Como naturalmente habra algunas variaciones segun el programa que utilicemos, lo voy a escribir de forma bastante general.

Primero definamos nuestras variables:

Por ejemple, en fortran usariamos algo como:

real:: B, H, A

Donde B será la variable que usaremos para la base, H para la altura, y A para el área.

Luego tenemos que escribir en pantalla algo que le diga al usario que debe introducir la base y el area.

Luego el programa debe ser capaz de leer ese input.

con algo de la forma:

B = read*input 1

H = read*input 2

Una vez tenemos definidas las variables, simplemente calculamos el área del triangulo:

A = H*B/2

Finalmente la podemos mostrar en pantalla con algo como:

print(A).

Lo que nos mostraría el valor del área.

Concluyendo, el diagrama en general sería:

  1. Definir variables
  2. Pedirle al usuario que introduzca los valores deseados (de las variables).
  3. Leer los valores deseados y asignarlo a la variable correspondiente.
  4. Realizar la operación para calcular el área.
  5. Mostrar en pantalla el resultado.

Si quieres aprender más, puedes leer:

brainly.com/question/21949109

5 0
2 years ago
An electron (q=-1.602×10-19C) is placed .03m away from spherical object with a net charge of -7.2 C.
vovangra [49]

Answer:

Explanation:

electric field at the location of electron

= 9 x 10⁹ x 7.2 / .03²

= 72 x 10¹² N/C

force on electron = electric field x charge on electron

= 72 x 10¹² x 1.6 x 10⁻¹⁹

= 115.2 x 10⁻⁷ N .

C )

work done = charge on electron x potential difference at two points

potential at .03 m

= 9 x 10⁹ x 7.2 / .03

= 2.16 x 10¹² V

potential at .001 m

= 9 x 10⁹ x 7.2 / .001

= 64.8 x 10¹² V

potential difference = (64.8 - 2.16 )x 10¹² V

= 62.64 x 10¹² V  .

work done = 62.64 x 10¹² x 1.6 x 10⁻¹⁹

= 100.224 x 10⁻⁷ J .

D )

There will be no change in the magnitude of force on positron except that the direction of force will be reversed . In case of electron , there will be repulsion and in case of positron , there will be attraction .

Work done in case of electron will be positive and work done in case of positron will be negative .

electric field due to charge will be same in both the cases .

8 0
2 years ago
Two identical copper blocks are connected by a weightless, unstretchable cord through a frictionless pulley at the top of a thin
likoan [24]

Answer:

13.6 N

Explanation:

Since one side of the wedge is vertical and the wedge makes and angle of 33 with the horizontal, the angle between the weight of the copper block on the incline and the incline is thus 90 - 33 = 57.

Let M be the mass of the block that hangs, m be the mass of the block on the incline and T be the tension in the weightless unstretchable cord.

We assume the motion is downwards in the direction of the hanging block, M.

We now write equations of motion for each block.

So

Mg - T = Ma    (1) and T - mgcos57 - F = ma where F is the frictional force on the block on the incline and a is their acceleration.

Now, since both blocks do not move, a = 0.

So, Mg - T = M(0) = 0     and T - mgcos57 - F = m(0) = 0

Mg - T = 0    (3) and T - mgcos57 - F = 0 (4)

From (3), T = Mg

Substituting T into (4), we have

T - mgcos57 - F = 0

Mg - mgcos57 - F = 0

So, Mg - mgcos57 = F  

F = Mg - mgcos57

F = (M - mcos57)g

Since g = acceleration due to gravity = 9.8 m/s², and M = 2.94 kg and m = 2.85 kg.

We find F, thus

F = (2.94 kg - 2.85 kgcos57)9.8 m/s²

F = (2.94 kg - 2.85 kg × 0.5446)9.8 m/s²

F = (2.94 kg - 1.552 kg)9.8 m/s²

F = (1.388 kg)9.8 m/s²

F = 13.6024 kgm/s²

F ≅ 13.6 N

6 0
3 years ago
An incident ray that passes through the vertex of a convex lens:
WINSTONCH [101]
The answer is refracts parallel to the axis of the lens
7 0
2 years ago
Other questions:
  • How much power is expended if you lift a 60 n crate 10 meters in 1 second?
    6·1 answer
  • Salina’s internal desire to exercise is called
    5·2 answers
  • You are making a 568b utp crossover cable that will be used to cascade two switches on an ethernet network. you have attached an
    13·1 answer
  • How does the sum of forces help you
    8·2 answers
  • An older-model car accelerates from 0 to speed v in 9.0 s. A newer, more powerful sports car of the same mass accelerates from 0
    13·1 answer
  • If pressure of a gas is increased in its volume at constant what will happen to its temperature
    13·2 answers
  • If the distance between two objects is increased,the gravitational attraction between them will.....?
    5·2 answers
  • What amount of force is needed to propel and object of 27 kg to an acceleration of 11,550 m/s^2? (1 point)
    13·1 answer
  • Now write a short paragraph comparing "fast" to "speeding up quickly" and "slow" to "speeding up slowly".
    5·1 answer
  • What is kinetic energy
    9·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!