Un vehículo parte del reposo y acelera constantemente a 6 m/s2

an elevator mass of 7700 kg falls from a height of 32 m after a sudden failure in the hoisting cable. The mass is stopped by a s

valkas [14]

Answer:k=28.29 kN/m

Explanation:

Given

mass $m =7700 kg$

height from which Elevator falls $h=32 m$

Let x be the compression in the spring

thus From conservation of Energy Potential energy will convert in to Elastic Potential Energy of spring

$\frac{kx^2}{2}=mg(h+x)$ ----------1

also maximum acceleration is 5g

thus

$mg-kx=ma$

here $a=-5g$

$kx=mg-m(-5g)=6mg$

$x=\frac{6mg}{k}$

Substitute x in equation 1

$0.5\times k\times (\frac{6mg}{k})^2=mg(h+\frac{6mg}{k})$

$18\frac{(mg)^2}{k}=mgh+6\frac{(mg)^2}{k}$

$k=12\cdot \frac{mg}{h}$

$k=12\times \frac{7700\times 9.8}{32}$

$k=28.29 kN/m$

4 0

2 years ago

To travel at constant speed, a car engine provides 24KW of useful power. The driving force on the car is 600N. At what speed doe

Keith_Richards [23]

Answer:

The speed traveled by the car is 40 meter per second.

Explanation:

The formula for the relation between the power and the force is as follows:

P = Fv

Where F is the force and v is the speed.

As given

To travel at constant speed, a car engine provides 24KW of useful power. The driving force on the car is 600N.

F = 600 N

Convert power from KW to W.

1 KW = 1000 W

24 KW = 24 × 1000 W

= 24000 W

Thus

P = 24000 W

Put these values in the formula.

24000 = 600 × v

24000 = 600v

$v = \frac{24000}{600}$

v = 40 meter per second .

Therefore the speed of the car is 40 meter per second .

3 0

3 years ago

You push very hard on a heavy desk, trying to move it. You do work on the desk:

frozen [14]

Answer:

(C) Only if it starts moving

Explanation:

We know that work done is given by

$W=F.d=Fdcos\Theta$

So there are two case in which work done is zero

First case is that when force and displacement are perpendicular to each other

And other case is that when there is no displacement

So for work to be done there must have displacement, if there is no displacement then there is no work done

So option (c) will be the correct option

3 0

3 years ago

When U-235 splits, it usually emits

Serga [27]

Splitting atoms. 'Fission' is another word for splitting. The process of splitting a nucleus is called nuclear fission. ... For fission to happen, the uranium-235 or plutonium-239 nucleus must first absorb a neutron.

5 0

3 years ago

Discuss how friction is reduced in oce skating

belka [17]

Answer:

below

Explanation:

Ice melts, meaning it has a watery layer upon its surface. This allows things to be moving like they are on a liquid but it has the solidity of a solid. The thin metal of the ice skates also decrease the surface area meaning it exerts more force but in turn, it allows you to move faster and further reduces friction.

7 0

2 years ago