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andrew-mc [135]
3 years ago
14

A 150 N boy rides a 60 N bicycle a total of 200 m at a constant speed. The frictional force against the forward motion of the bi

cycle equals 35 N. How much work does the boy do? (Hint: Do sum of all forces first.)
Physics
1 answer:
soldier1979 [14.2K]3 years ago
8 0

Answer:

W = 7000 J

Explanation:

To solve this problem we use that the speed of the bicycle is constant, therefore its acceleration is zero

            F -fr = 0

            F = fr

where F is the force applied by the child

Work is defined by

           W = F. x

           W = F x cos θ

in this case the child's force is parallel to the movement, therefore the angle is zero and cos 0 = 1

           

let's calculate

           W = 35 200

           W = 7000 J

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¿Cuál es la magnitud y dirección de la aceleración de los cuerpos en caída libre en el planeta Tierra?
Tatiana [17]

La magnitud es de 9.8 m/s² ... la aceleración de la gravedad en o cerca de la superficie de la Tierra.

La dirección es hacia el centro de la Tierra. (Llamamos a esa dirección "abajo").

6 0
3 years ago
Suppose your car is on a 5% grade, meaning that for every 100 m you travel along the road you raise or lower only 5 m in elevati
kvv77 [185]

Answer:

734.215N

Explanation:

First we calculate the angle that corresponds to a 5% slope using the Tan-1 function

\beta = tan-1(5%)=2.86

then we use the component that corresponds to the direction parallel to the road, additionally we must multiply by the gravity value to find the weight(g=9.81m/s^2)

Wx=M*g*sen(2.86)=1500kg*9.81*sen(2.86)=734.215N

8 0
3 years ago
Read 2 more answers
Se golpea una pelota de golf de manera que su velocidad inicial forma un ángulo de 45° con la horizontal. La pelota alcanza el s
nordsb [41]

Answer:

42m/s

6.06s

Explanation:

To find the initial velocity and time in which the ball is fling over the ground you use the following formulas:

x_{max}=\frac{v_o^2sin(2\theta)}{g}\\\\x_{max}=vt_{max}

θ: angle = 45°

vo: initial velocity

g: gravitational constant = 9.8m/s^2

x_max: max distance = 180 m

t_max: max time

by replacing the values of the parameters and do vo the subject of the first formula you obtain:

v_o=\sqrt{\frac{gx_{max}}{sin(2\theta)}}\\\\v_o=\sqrt{\frac{(9.8m/s^2)(180m)}{sin(2(45\°))}}=42\frac{m}{s}

with this value of vo you calculate the max time:

t_{max}=\frac{x_{max}}{v}=\frac{x_{max}}{v_ocos(45\°)}\\\\t_{max}=\frac{180m}{(42m/s)cos(45\°)}=6.06s

hence, the initial velocity of the ball is 42m/s and the time in which the ball is in the air is 6.06s

- - - - - - - - - - - - -- - - - - - - - - - - - - -

TRANSLATION:

Para encontrar la velocidad inicial y el tiempo en el que la pelota está volando sobre el suelo, use las siguientes fórmulas:

θ: ángulo = 45 °

vo: velocidad inicial

g: constante gravitacional = 9.8m / s ^ 2

x_max: distancia máxima = 180 m

t_max: tiempo máximo

reemplazando los valores de los parámetros y haciendo el tema de la primera fórmula que obtiene:

con este valor de vo usted calcula el tiempo máximo:

por lo tanto, la velocidad inicial de la pelota es de 42 m / sy el tiempo en que la pelota está en el aire es de 6.06 s

4 0
2 years ago
Which is a correct example of the principle of conservation of momentum? A) reversing of a car at a dead end B) conversion of ra
Hunter-Best [27]
I think the answer would be D.
3 0
3 years ago
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A system consists of electrons and protons only. It contains 150 electrons and has a total charge of +22e. What is the mass of t
liubo4ka [24]

According to the statements the number of electrons is 150, then

e = 150

But there is a positive charge of +22e, then the number of protons would be

p = 150+172

If the mass of the electrons is

m_e = 9.11*10^{-31} kg

And the mass of the protong is

m_p = 1.673*10^{-27}kg

We have that the total mass of the system would be

m = e*m_e +pm_p

m = 150 * (9.11*10^{-31})+170(1.673*10^{-27})

m = 2.84547*10^{-25} kg

5 0
3 years ago
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