Convert 557.2 to scientific notation

In which one(s) of the following situations will there be an INCREASE in Kinetic Energy? Group of answer choices A block slides

Maksim231197 [3]

Answer:

The Kinetic Energy INCREASE in the following situations:

a)A block slides down a frictionless incline:

e)A merry go round rotates faster due to the push by a person.

Explanation:

The energy kinetics is proportional to the square of the velocity:

$E_k=1/2*mv^2$

We study the cases:

a)A block slides down a frictionless incline:

The gravity made a positive work and the box get a extra velocity, then the kinetics energy INCREASE

b)A box is pulled across a rough floor at constant speed:

The magnitude of the velocity does not change, so the kinetics energy does not change as well

c)A stone at the end of a string is whirled in a horizontal circle at constant speed:

The magnitude of the velocity does not change, so the kinetics energy does not change as well

d)A projectile approaches its maximum height:

If the projectile approaches its maximum height, its velocity approaches to zero. Then the kinetics Energy DECREASE

e)A merry go round rotates faster due to the push by a person.

Thanks to the push, the magnitude of the velocity INCREASE, so the kinetics energy INCREASE as well

6 0

3 years ago

__________ is when a person becomes less sensitive to a drug. A. Tolerance B. Craving C. Addiction D. Dependence

Luden [163]

A) Tolerance

Tolerance is developed after using a drug repeatedly, so the body adapts to it. Because of that, people who develop a tolerance would then need to use more of that drug to get the same effect.

4 0

3 years ago

Why does the mass spectrum of Br2 contain three signals whose heights are almost in the ratio of 1:2:1? What are the origins of

Eddi Din [679]

<span>The element bromine has two isotopes: Br-79 and Br-81, with a 50%-50% isotopic abundance. Statistically, 25% of bromine molecules will be Br79-Br79, 25% will be Br81-Br81 and 50% will be Br79-Br81. This is equivalent to a ratio of 1:1:2 or 1:2:1. The peaks in a mass spectrum just like chromatography reflect this relative abundance of different isotopic combinations.</span>

3 0

3 years ago

A jet plane lands with a velocity of +107 m/s and can accelerate at a maximum rate of -5.18 m/s2 as it comes to rest. From the i

Marrrta [24]

Answer:

20.7 s

Explanation:

The equation to calculate the velocity for a uniform acceleration a, time t and initial velocity v₀:

v = a*t + v₀

Solve for t:

t = (v - v₀)/a

3 0

3 years ago

A circular loop of wire with radius r=0.0250 m and resistance r=0.390 ohms is in a region of spatially uniform magnetic field. t

slavikrds [6]

Answer:

0.0133 A

Explanation:

The time at which B=1.33 T is given by

1.33 = 0.38*t^3

t = (1.33/0.38)^(1/3) = 1.52 s

Using Faraday's Law, we have

emf = - dΦ/dt = - A dB/dt = - A d/dt ( 0.380 t^3 )

Area A = pi * r² = 3.141 *(0.025 *0.025) = 0.00196 m²

emf = - A*(3*0.38)*t^2

thus, the emf at t=1.52 s is

emf = - 0.00196*(3*0.38)*(1.52)^2 = -0.0052 V

if the resistance is 0.390 ohms, then the current is given by

I = V/R = 0.0052/0.390 = 0.0133 A

3 0

3 years ago