A force is a push or pull in? A.a circle B.an arc C.a straight line

Need help with these 3 questions pls help

Burka [1]

Answer:

Explanation:

First one is passion i think

second one is true im not sure

Third one is Time managaemant

Hope this helps!

8 0

3 years ago

In crash tests, a shock absorber is used to slow the test car. The shock absorber consists of a piston with small holes that mov

Lesechka [4]

Answer:

The heat transferred to water equals 1600 kJ

Explanation:

By the conservation of energy we have

All the kinetic energy of the moving vehicle is converted into thermal energy

We know that kinetic energy of a object of mass 'm' moving with a speed of 'v' is given by

$K.E=\frac{1}{2}mv^{2}$

Thus

$K.E_{car}=\frac{1}{2}\times 2000\times 40^{2}=1600\times 10^{3}Joules$

Thus the heat transferred to water equals $1600kJ$

3 0

3 years ago

The force of T = 20 N is applied to the cord of negligible mass. Determine the angular velocity of the 20-kg wheel when it has r

horrorfan [7]

Image of wheel is missing, so i attached it.

Answer:

ω = 14.95 rad/s

Explanation:

We are given;

Mass of wheel; m = 20kg

T = 20 N

k_o = 0.3 m

Since the wheel starts from rest, T1 = 0.

The mass moment of inertia of the wheel about point O is;

I_o = m(k_o)²

I_o = 20 * (0.3)²

I_o = 1.8 kg.m²

So, T2 = ½•I_o•ω²

T2 = ½ × 1.8 × ω²

T2 = 0.9ω²

Looking at the image of the wheel, it's clear that only T does the work.

Thus, distance is;

s_t = θr

Since 4 revolutions,

s_t = 4(2π) × 0.4

s_t = 3.2π

So, Energy expended = Force x Distance

Wt = T x s_t = 20 × 3.2π = 64π J

Using principle of work-energy, we have;

T1 + W = T2

Plugging in the relevant values, we have;

0 + 64π = 0.9ω²

0.9ω² = 64π

ω² = 64π/0.9

ω = √64π/0.9

ω = 14.95 rad/s

4 0

4 years ago

Tungsten is being used at half its melting point (Tm≈3,400◦C) and astress level of 160 MPa. An engineer suggests increasing the

Paladinen [302]

Answer:

Explanation:

The missing diagram is attached in the image below which shows the deformation map of the Tungsten.

Given that:

Stress level $\sigma = 160 MPa$

T = 0.5 Tm

$\implies \dfrac{T}{Tm} = 0.5$

G = 160 GPa

$\implies \dfrac{\sigma}{G} = 10^{-3}$

a)

The regulating creep mechanism is dislocation driven, as we can see from the deformation mechanism.

The engineer's recommendation would not be approved because increasing grain size results in a decrease in the grain-boundary count, preferring dislocation motion. The existence of grain borders is a hindrance to dislocation motion, as the dislocation principle explicitly states. To stop the motion, we'll need a substance with finer grains, which would result in more grain borders, or a material with higher pressure. In the case of Nabarro creep, which is diffusion-driven, an engineer's recommendation would be useful.

b)

If stress level reduced to $\sigma = 1.6 MPa$

$\implies \dfrac{\sigma }{G} = 10^{-5}$

Cable creep is now the controlling creep mode, which entails tension-driven atom diffusion along grain borders to elongate grain along the stress axis, a process known as grain-boundary diffusion. Cable creep is more common in fine-grained materials. As a result, the engineer's advice would succeed in this case. The affinity for cable creep is reduced when the grain size is increased.

c)

From the map of creep mechanism for $\dfrac{\sigma}{G} = 10^{-3} \ and \ \dfrac{T}{Tm} = 0.5$