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2 years ago

a 10-N force is exerted on a box, moving it 20 m in the same direction. What is the magnitude of work done on the box?

1 answer:

8 0

F = 10 N

d = 20 m

θ = 0°

W = F (dot product) D = F * D * cos(angle between them)

W = FDcosθ

W = 10 * 20 * cos0 = 200 J

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6. A 145-g baseball moving 30.5 m/s strikes a stationary 5.75-kg brick resting on small rollers so it moves without significant

Sindrei [870]

Answer:

Explanation:

a )

momentum of baseball before collision

mass x velocity

= .145 x 30.5

= 4.4225 kg m /s

momentum of brick after collision

= 5.75 x 1.1

= 6.325 kg m/s

Applying conservation of momentum

4.4225 + 0 = .145 x v + 6.325 , v is velocity of baseball after collision.

v = - 13.12 m / s

b )

kinetic energy of baseball before collision = 1/2 mv²

= .5 x .145 x 30.5²

= 67.44 J

Total kinetic energy before collision = 67.44 J

c )

kinetic energy of baseball after collision = 1/2 x .145 x 13.12²

= 12.48 J .

kinetic energy of brick after collision

= .5 x 5.75 x 1.1²

= 3.48 J

Total kinetic energy after collision

= 15.96 J

3 0

3 years ago

The data indicate the populations of mammals in the Florida Everglades in different years over the past two decades. The Burmese

soldier1979 [14.2K]

Answer:

C) Burmese pythons lack natural predators and can utilize a wide variety of food sources in the Everglades.

Explanation:

Due to it being an invasive specie (naturally found in South Asia), and also one of the five largest species of snakes in the world, the Burmese pythons lack natural predators in this new territories.

The Burmese viper is also an opportunistic hunter and would eat anything it can overpower, it easily made a wide range of food varieties in these swamps.

8 0

3 years ago

he membrane that surrounds a certain type of living cell has a surface area of 6.0 x 10-9 m2 and a thickness of 1.6 x 10-8 m. As

k0ka [10]

Answer:

$1.54481175\times 10^{-12}\ C$

Explanation:

$\epsilon_0$ = Permittivity of free space = $8.85\times 10^{-12}\ F/m$

A = Area = $6\times 10^{-9}\ m^2$

d = Thickness = $1.6\times 10^{-8}\ m$

k = Dielectric constant = 5.4

V = Voltage = 86.2 mV

Charge is given by

$Q=CV\\\Rightarrow Q=k\epsilon\dfrac{A}{d}V\\\Rightarrow Q=5.4\times 8.85\times 10^{-12}\times \dfrac{6\times 10^{-9}}{1.6\times 10^{-8}}\times 86.2\times 10^{-3}\\\Rightarrow Q=1.54481175\times 10^{-12}\ C$

The charge on the outer surface is $1.54481175\times 10^{-12}\ C$

4 0

2 years ago

Pierre cycles at 4 miles per hour and travels a distance of 13 miles. How long

amm1812

Answer:

His journey took him 3 hours 15 minutes.

Explanation: 4 miles every hour. So 1 hr is equal to 4 miles, 2 hrs is equal to 8 miles, 3 hrs is equal to 12 miles. Now he just has 1 miles left, and since it takes him a hour to cycle 4 miles, 60 divided by 4 is 15. Therefore, 1 mile is equal to 15 minutes.

4 0

3 years ago

Read 2 more answers

The concrete slab of a basement is 11 m long, 8 m wide, and 0.20 m thick. During the winter, temperatures are nominally 17 C and

Lunna [17]

Answer:

Q = - 4312 W = - 4.312 KW

Explanation:

The rate of heat of the concrete slab can be calculated through Fourier's Law of heat conduction. The formula of the Fourier's Law of heat conduction is as follows:

Q = - kA dt/dx

Integrating from one side of the slab to other along the thickness dimension, we get:

Q = - kA(T₂ - T₁)/L

Q = kA(T₁ - T₂)/t

where,

Q = Rate of Heat Loss = ?

k = thermal conductivity = 1.4 W/m.k

A = Surface Area = (11 m)(8 m) = 88 m²

T₁ = Temperature of Bottom Surface = 10°C

T₂ = Temperature of Top Surface = 17° C

t = Thickness of Slab = 0.2 m

Therefore,

Q = (1.4 W/m.k)(88 m²)(10°C - 17°C)/0.2 m

<u>Here, negative sign shows the loss of heat.</u>

3 0

3 years ago