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3 years ago

Which of the following statements is false?

Physics

2 answers:

lys-0071 [83]3 years ago

6 0

It is false that sound waves are the only waves that reflect.

Answer: Option A

<u>Explanation:</u>

Reflection of the waves means that it is a process when waves hit any object, they bounce off from that object. Sound waves are not the only waves which reflect. Other waves which reflect are infrared waves and the radio waves.

Light waves might move through the material which is known as the process of refraction or might even bounce off the material, hence the light waves may or may not reflect. Thus there are other waves also which reflect from the objects.

Pie3 years ago

3 0

A is false because light and sound waves can both reflect off of objects

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In a lab, the mass of object A is 2.5 kg. Object A weighs:

kondor19780726 [428]

Weight of object = mass x acceleration due to gravity
= 2.5 x 9.8
= 24.5N

Hence option B is correct.
Hope this helps!!

5 0

4 years ago

Read 2 more answers

As shown in the diagram below, a rope attached to a 500.-kilogram crate is used to exert a force of 45 newtons at an angle of 65

kaheart [24]

Answer:

19.01 N

Explanation:

F = Force being applied to the crate = 45 N

$\theta$ = Angle at which the force is being applied = $65^{\circ}$

Horizontal component of force is given by

$F_x=F\cos\theta\\\Rightarrow F_x=45\times \cos65^{\circ}\\\Rightarrow F_x=19.01\ \text{N}$

The horizontal component of the force acting on the crate is 19.01 N.

4 0

3 years ago

An alternative to CFL bulbs and incandescent bulbs are light-emitting diode (LED) bulbs. A 16-W LED bulb can replace a 100-W inc

Yanka [14]

Answer:

LED bulb = 0.145 A

Incandescent bulb = 0.909 A

CFL bulb = 0.218 A

Explanation:

Given:

Power rating of LED bulb (P₁) = 16 W

Power rating of incandescent bulb (P₂) = 100 W

Power rating of CFL bulb (P₃) = 24 W

Terminal voltage across the circuit (V) = 110 V

We know that, power is related to terminal voltage and current drawn as:

$P=VI$

Express this in terms of 'I'. This gives,

$I=\frac{P}{V}$

Now, calculate the current drawn in each bulb using their respective values.

For LED bulb, $P_1=16\ W, V=110\ V$

So, current drawn is given as:

$I_1=\frac{16\ W}{110\ V}=0.145\ A$

For incandescent bulb, $P_2=100\ W, V=110\ V$

So, current drawn is given as:

$I_2=\frac{100\ W}{110\ V}=0.909\ A$

For CFL bulb, $P_3=24\ W, V=110\ V$

So, current drawn is given as:

$I_3=\frac{24\ W}{110\ V}=0.218\ A$

Therefore, the currents drawn through LED bulb, incandescent bulb and CFL bulb are 0.145 A, 0.909 A and 0.218 A respectively.

5 0

4 years ago

A car slows from 27 m/s to 5 m/s with a constant acceleration for 6.87 s. What is the car’s acceleration?

Kobotan [32]

In this case, the movement is uniformly delayed (the final rapidity is less than the initial rapidity), therefore, the value of the acceleration will be negative.

1. The following equation is used:

a = (Vf-Vo)/ t

a: acceleration (m/s2)

Vf: final rapidity (m/s)

Vo: initial rapidity (m/s)

t: time (s)

2. Substituting the values in the equation:

a = (5 m/s- 27 m/s)/6.87 s

3. The car's acceleration is:

a= -3.20 m/ s<span>^2</span>

5 0

3 years ago

A locomotive is pulling 15 freight cars, each of which is loaded with the same amount of weight. The mass of each freight car (w

VMariaS [17]

Answer:

298,220 N

Explanation:

Let the force on car three is T_23-T_34

Since net force= ma

from newton's second law we have

T_23-T_34 = ma

therefore,

T_23-T_34 = 37000×0.62

T_23= 22940+T_34

now, we need to calculate

T_34

Notice that T_34 is accelerating all 12 cars behind 3rd car by at a rate of 0.62 m/s^2

F= ma

So, F= 12×37000×0.62= 22940×12= 275280 N

T_23 =22940+T_34= 22940+ 275280= 298,220 N

therefore, the tension in the coupling between the second and third cars

= 298,220 N

3 0

3 years ago