The picture below shows a person swinging a toy plane attached to a string in

A ball has a diameter of 3.77 cm and average density of 0.0839 g/cm3. What force is required to hold it completely submerged und

mestny [16]

Answer:

0.25 N

Explanation:

The density of the ball ( $\rho_b$ ) = 0.0839 g/cm³ = 83.9 kg/m³

The density of water ( $\rho_w$ ) = 1000 kg/m³

diameter = 3.77 cm = 0.0377 m

radius of ball = 0.0377/2 = 0.01885 m

The volume (V) = $\frac{4}{3} \pi r^3=\frac{4}{3}*\pi*0.01885^3=2.8*10^{-5}\ m^3$

Let us assume the acceleration due to gravity (g) = 9.8 m/s²

Hence:

The force is required to hold it completely submerged under water (F) is:

$F=\rho_w Vg-\rho_b Vg=1000*(2.8*10^{-5})*9.81-83.9*(2.8*10^{-5})*9.81\\\\$

F = 0.25 N

7 0

3 years ago

A horizontal force of 750 N is needed to overcome the force of static friction between a level floor and a 250-kg crate. If g-9.

seraphim [82]

Answer:

0.31

Explanation:

horizontal force, F = 750 N

mass of crate, m = 250 kg

g = 9.8 m/s^2

The friction force becomes applied force = 750 N

According to the laws of friction,

Friction force = μ x Normal reaction of the surface

here, μ be the coefficient of friction

750 = μ x m g

750 = μ x 250 x 9.8

μ = 0.31

Thus, the coefficient of static friction is 0.31.

7 0

3 years ago

Which is not an assumption about particles in a gas according to the kinetic theory?

bearhunter [10]

Let us evaluate the given assumptions according to the kinetic theory for an ideal gas.

a.
The motion of one particle is unaffected by other particles unless the particles collide.
TRUE. The particles are in random motion unless they collide.

b.
The forces of attraction among particles keep the particles close together.
FALSE. No forces act between particles except during collision.

c.
Under ordinary conditions, forces of attraction between particles can be ignored.
TRUE.

Answer: Statement b is false because it is not an assumption.

4 0

3 years ago

Suppose you exert 150 n on your refrigerator and push it across the kitchen floor at constant velocity. what friction force acts

Pachacha [2.7K]

Due that the velocity is constant that means that friction force is equal to the force exert by you, otherwise the refrigerator will accelerate or decelerate and in both cases velocity will not be constant.
So then the friction force between refrigerator and floor is 150 Newtons.

8 0

3 years ago

Read 2 more answers

A 2-lb slider is propelled upward at A along the fixed curved bar which lies in a vertical plane. If the slider is observed to h

timofeeve [1]

To develop this problem it is necessary to apply the concepts given in the balance of forces for the tangential force and the centripetal force. An easy way to detail this problem is through a free body diagram that describes the behavior of the body and the forces to which it is subject.

PART A) Normal Force.

$F_n = \frac{mv^2}{r}$

$N+mgcos\theta = \frac{mv^2}{r}$

Here,

Normal reaction of the ring is N and velocity of the ring is v

$N+mgcos\theta = \frac{mv^2}{r}$

$N+Wcos\theta = \frac{W}{g} (\frac{v^2}{r})$

$N+2cos30\° = \frac{2}{32.2}*\frac{10^2}{2}$

$N = 1.374lb$

PART B) Acceleration

$F_t = ma_t$

$-mgsin\theta = ma_t$

$-W sin\theta = \frac{W}{g} a_t$

$-2Sin30\° = (\frac{2}{32.2})a_t$

$a_T = -16.10ft/s^2$

Negative symbol indicates deceleration.

<em>NOTE: For the problem, the graph in which the turning radius and the angle of suspension was specified was not supplied. A graphic that matches the description given by the problem is attached.</em>

8 0

3 years ago