the acceleration of a body in free fall depends on the place or the world in which it is, true or false?

When the rubber sheet is pulled down, the volume of the bell jar is ____________ and the pressure in the bell jar is ___________

Makovka662 [10]

Answer:

increases, decreases, respiration

8 0

2 years ago

A golf club exerts an average horizontal force of 1005 N in the –x direction on a 453 grams golf ball that is initially at rest

adelina 88 [10]

Answer:

The impulse is 1.89 Ns and final velocity of the golf 4.17 $\frac{m}{s}$

Explanation:

Given:

Average force $F = 1005$ N

Contact time $t = 1.89 \times 10^{-3}$ sec

Mass of golf ball $m = 453 = 0.453$ kg

(a)

Impulse is given by,

$J = Ft$

$J = 1005 \times 1.89 \times 10^{-3}$

$J = 1.89$ Ns

(b)

For finding the final velocity,

$J = \Delta P$

$J = mv$

$1.89 = 0.453 v$

$v = 4.17 \frac{m}{s}$

Therefore, the impulse is 1.89 Ns and final velocity of the golf 4.17 $\frac{m}{s}$

7 0

3 years ago

the minimum flying speee for a bird called a house martin is 9.0ms^-1. it reaches this speed by falling from its nest before swo

Lilit [14]

Answer:

The nest must be about 4.15 meters above ground

Explanation:

Use the velocity equation under accelerated motion (acceleration of gravity ):

$v_f=v_i+a\,*\,t$

which for this case has initial velocity = 0 (falls from the nest), final velocity = 9 m/s, and a = 9.8 m/s^2, then we can find the time needed in air while falling to reach the required speed:

$v_f=v_i+a\,*\,t\\9=0+9.8\,t\\t=\frac{9}{9.8} \, sec\\t \approx 0.92\,\, sec$

We now use this time value to find the distance covered in free fall during 0.92 seconds:

$d=\frac{1}{2} \,9.8 \,t^2=4.9\,(0.92)^2=4.147 \,meters\approx 4.15\,meters$

8 0

3 years ago

A loaded ore car has a mass of 950 kg and rolls on rails with negligible friction. It starts from rest and is pulled up a mine s

Ierofanga [76]

Answer:

a). P=11.04kW

b). Pmax=11.38 kW

c). Wt=6423.166kJ

Explanation:

The power of the motor when the speed is constant is the work in a determinate time.

$P=\frac{W}{t}$

The work is the force the is applicated in a distance so

W=F*d

replacing:

$P=F*\frac{d}{t}$ and $\frac{d}{t}$ determinate distance in time is velocity so

a).

$P=F*v$

$F=m*a\\F=m*g*sin(33.5)$

$P=950kg*9.8\frac{m}{s^{2}}*sin(33.5)*2.15\frac{m}{s}\\P=11047.846 W\\P=11.0478 kW$

b).

The maximum power must the motor provide, is the maximum force with the maximum speed of the motor in this case

The first step is find the acceleration so

$vi=0\frac{m}{s} \\vf=2.15 \frac{m}{s}\\vf=vi+a*t\\vf-vi=a*t\\ a=\frac{vf-vi}{t}= a=\frac{2.15\frac{m}{s}-0\frac{m}{s}}{13s}\\a=0.1653 \frac{m}{s^{2}}$

The maximum force is when the car is accelerating so

$Ft=Fa+Fg\\Ft=m*a+m*g*sin(33.5)\\Ft=950kg*0.1653\frac{m}{s^{2}}+950*9.8\frac{m}{s^{2}}*sin(33.5)\\Ft=5295.565 N$

so the maximum force is the maximum force by the maximum speed

$Pmax=Ft*v\\Pmax=5295.565N*2.15\frac{m}{s}\\Pmax=11385.46\\Pmax=11.3854kW$

c).

The total energy transfer without any friction is the weight move in the high axis y in this case, so is easy to know that distance

W=m*g*h

h=Length*sin(33.5)

W=m*g*Length*sin(33.5)

W=950 kg*9.8* 1250m*sin(33.5)

W=6423166.667 kJ

W=6423.166 kJ

4 0

4 years ago

Explain why it is important that the balloon is made from an electrical insulator.

aleksandr82 [10.1K]

Explanation:

object made of rubber, such as the ballons are elecrical insulators, meaning that they resist electric charges flowing through them..

when the ballon has been rubbed enough times to gain a sufficient negative charge, it will be attracted to the wall

8 0

3 years ago

the acceleration of a body in free fall depends on the place or the world in which it is, true or false?​

the acceleration of a body in free fall depends on the place or the world in which it is, true or false?