What is the name of Newton's first law of motion?

Acceleration always involves a change in

Scrat [10]

Velocity. Since velocity consists of a speed and a direction, acceleration is a change in speed, or direction, or both.

5 0

3 years ago

A woman pushes a 27 kg lawnmower at a steady speed. She exerts a 120 N force in a direction 35◦ below the horizontal. The accele

nikklg [1K]

The vertical force exerted on the lawn is 68.8 N downward

Explanation:

The vertical force exerted by the lawnmower on the lawn is equal to the vertical component of the force applied, therefore:

$F_y = F sin \theta$

where

F is the magnitude of the force applied

$\theta$ is the angle between the direction of the force and the horizontal

In this problem:

F = 120 N

$\theta=-35^{\circ}$

Substituting,

$F_y = (120)(sin 30)=-68.8 N$

where the negative sign means the direction of the force is downward.

Learn more about vector components and forces here:

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#LearnwithBrainly

3 0

3 years ago

Why freezer is made in the upper part of refrigrator

svp [43]

<h2>Question</h2>

why freezer is made in the upper part of refrigrator

<h2>✒ Answer</h2>

the cold air produced from it is denser than the warmer air in the bottom

<h3>Explaination</h3>

Freezer is normally provided at the top of the refrigerator, because density of the cold air is high compared to the hot air. In a refrigerator the air contacts with the cooling coil and gets cooling.Because of the high density the cold air gets down and the warm air/hot air moves upward and gets cooling from the cooling coil/evaporator coil. This process is repeated. If the Freezer is provided at the bottom place of the refrigerator, the cold air can't to move full area of the refrigerator. So the freezer is normally provided at the top at the refrigerator

4 0

3 years ago

A heavy piece of hanging sculpture is suspended by a 90 cm-long, 5.0 g steel wire. When the wind blows hard, the wire hums at it

kupik [55]

Answer: The mass of the sculpture is 11.8kg

Explanation:

Using the equation of fundamental frequency of a taut string.

f = (1/2L)*√(T/μ) .... (Eqn1)

Where

f= frequency in Hertz =80Hz

T = Tension in the string = Mg

M represent the mass of the substance (sculpture) =?

g= 9.8m/s^2

L= Length of the string=90cm=0.9m

μ= mass density = mass of string /Length of string

mass of string =5g=0.005kg

L=0.9m

μ=0.005/0.9 = 0.0056kg/m

Using (Eqn1)

80= 1/(2*0.9) √(T/0.0056)

144= √(T/0.0056)

Square both sides

20736= T/0.0056

T= 116.12N

Recall that T =Mg

116.12= M * 9.8

M=116.12/9.8

M= 11.8kg

Therefore the mass of the sculpture is 11.8kg

4 0

3 years ago

A potential difference of 1.20 V will be applied to a 33.0 m length of 18-gauge copper wire (diameter = 0.0400 in.). Calculate (

Nostrana [21]

Answer:A) Current = 1.739A, B)current density, J = 2.147x10^6 A/m2

magnitude of electric field , E = 0.036 N/C

)rate of thermal energy, P =2.086W

Explanation:

Resistance = R = ρL/A

But the cross-section area of the wire. is given as

Diameter / 2 = 0.04/2 =0.02in to m = 0.02 / 39.37= 0.000508

A = πr^2 = π x 0.000508^2 = 8.10 x 10^-7

since resistivity of copper,ρ= 17x10-9 ohm.m

so resistance is R = ρL/A

17x10-9 x 33 / 8.1x10-7

= 0.69 ohm.

A) Current = I = Voltage /Resistance =1.20/0.69 =1.739A

B)current density, J = Current /Area

= 1.739/8.1x10-7

= 2.147x10^6 A/m2

c)magnitude of electric field , E = Current density x resistivity =J ρ

E = 2.147 x 10^6 x 17 x 10^-9

E = 0.036 N/C

D)rate of thermal energy, P = I² R =1.739² X 0.69

=2.086W

6 0

3 years ago