3. J.J. Thomson discovered the electron in 1897. In 1904, he proposed a model

During a collision with a wall, the velocity of a 0.200-kg ball changes from 20.0 m/s toward the wall to 12.0 m/s away from the

mixas84 [53]

So the problem ask to calculate the magnitude of the average force applied to the ball if its mass is 0.2kg changes its velocity from 20m/s to 12m/s and the time contact with the ball with the wall is 60 ms. In my calculation the best answer would be 107N.

8 0

3 years ago

Arm abcd is pinned at b and undergoes reciprocating motion such that θ=(0.3 sin 4t) rad, where t is measured in seconds and the

storchak [24]

<span>θ=0.3sin(4t)
w=0.3cost(4t)(4)=1.2cost(4t)
a=-4.8sin(4t)

cos4t max will always be 1 (refer to cos graph), for same reason, sin4t will always be 0

therefore, wmax=1.2rad/s

vAmax=r*w=250*1.2=300mm/s
(may be different if your picture/radius is from a different picture)

adt=a*r=200*-4.8sin(4t)=0 (sin(4t)=0)

adn=r*w^2=200*1.2^2=288

ad= square root of adt^2+adn^2 = 288mm/s^2</span>

8 0

3 years ago

Sawyer launches his 180 kg raft on the Mississippi River by pushing on it with a force of 75N. How long must Sawyer push on the

Daniel [21]

Answer: 4.8 s

Explanation:

We have the following data:

$m=180 kg$ the mass of the raft

$F=75 N$ the force applied by Sawyer

$V=2 m/s$ the raft's final speed

$V_{o}=0 m/s$ the raft's initial speed (assuming it starts from rest)

We have to find the time $t$

Well, according to Newton's second law of motion we have:

$F=m.a$ (1)

Where $a$ is the acceleration, which can be expressed as:

$a=\frac{\Delta V}{\Delta t}=\frac{V-V_{o}}{t-t_{o}}$ (2)

Substituting (2) in (1):

$F=m\frac{V-V_{o}}{t-t_{o}}$ (3)

Where $t_{o}=0$

Isolating $t$ from (3):

$t=\frac{m(V-V_{o})}{F}$ (4)

$t=\frac{180 kg(2 m/s-0 m/s)}{75 N}$

Finally:

$t=4.8 s$

6 0

3 years ago

Dez pours water (n 1.333) into a container made of crown glass (n 1.52). The light ray in ner made of crown glass (n = 1.52). Th

siniylev [52]

Answer:

The angle of the corresponding refracted ray is 34.84°

Explanation:

Given that,

Refractive index of water n= 1.33

Refractive index of glass n= 1.52

Incident angle = 30.0°

We need to calculate the refracted angle

Using formula of Snell's law

$n_{i}\sin i=n_{r}\sin r$

Put the value into the formula

$\sin r=\dfrac{n_{i}\sin i}{n_{r}}$

$\sin r=\dfrac{1.52\times\sin30}{1.33}$

$\sin r=0.5714$

$r=sin^{-1}0.5714$

$r = 34.84^{\circ}$

Hence, The angle of the corresponding refracted ray is 34.84°

8 0

3 years ago

A horizontal pull A pulls two wagons over a horizontal frictionless floor, the first wagon is 500N, the second is 2000 N. The te

MrMuchimi

<span>The force will be zero if the wagons are moving at a constant speed (i.e. not accelerating), as there is no frictional force to overcome. If the wagons are accelerating, the force will be proportional to the acceleration, and 20% of the force applied by A.</span>

5 0

3 years ago