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3 years ago

A particle located at the position vector m has a force N acting on it. The torque about the origin is

Physics

1 answer:

choli [55]3 years ago

6 0

Complete question:

A particle located at the position vector r = (i + j) m has a force F = (2i + 3j) N acting on it. The torque about the origin is

Answer:

The torque about the origin is (5k) N.m

Explanation:

The torque about the origin is the vector or cross product of the two vectors.

τ = r x F (N.m)

Where;

τ is the torque about the origin

τ = r x F

τ = (i + j) x (2i + 3j)

For cross product;

i x j = k

i x k = j

j x k = i

i x i = 0

j x j = 0

k x k = 0

τ = (i + j) x (2i + 3j)

τ = (i x 2i) + (i x 3j) + (j x 2i) + (j x 3j)

τ = (0) + (3k)+ (2k) + 0

τ = (5k) N.m

Therefore, the torque about the origin is (5k) N.m

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A steel ball moves from a position of +125 meters to a position of -75 meters. This motion takes 90.0 seconds. What is the veloc

bonufazy [111]

Answer:

2.22m/s to the left

Explanation:

Given parameters:

Initial position = +125m

Final position = -75m

Motion time = 90s

Unknown:

Velocity of the steel ball = ?

Solution:

The velocity of the steel ball is given as the displacement divided by the time;

Velocity = $\frac{displacement}{time}$

The net displacement of the ball = 125- (-75) = 200m to the left

Input the parameters and solve for the velocity;

Velocity = $\frac{200}{90}$ = 2.22m/s to the left

3 0

4 years ago

Suppose the acceleration of an elevator is 1/2 g upward, then what is the reading on the scale in the elevator.

Irina-Kira [14]

Answer:

c. 3/2 mg

Explanation:

Given that the acceleration of an elevator is 1/2 g upward.

The reading on the scale of the elevator is the net external force acting on the elevator.

Let the force F acting on the elevator as shown,

By using Newton's 2nd law, $F_{net}=ma$

where, $F_{net}$ is the net force acting on the elevator.

m is the mass of the elevator,

a is the acceleration of the elevator, as given a=1/2 g upward.

So, $F_{net}=m\times \frac 1 2 g$

$F-mg=m\times \frac 1 2 g \\\\F=mg+ \frac 1 2 mg \\\\F= \frac 3 2 mg.$

So, the reading on the scale in the elevator is $\frac 3 2 mg$ .

Hence, option (c) is correct.

4 0

3 years ago

Where did the carbon in all living things come from?

Maru [420]

D (it was produced by cyanobacteria)!!!

3 0

3 years ago

Read 2 more answers

On a part-time job, you are asked to bring a cylindrical iron rod of density 7800 kg/m3 , length 92.6 cm and diameter 2.95 cm fr

slavikrds [6]

Answer:

48.4293354946 N

Yes

Explanation:

d = Diameter of rod = 2.95 cm

h = Length of rod = 92.6 cm

$\rho$ = Density of rod = 7800 kg/m³

g = Acceleration due to gravity = 9.81 m/s²

Volume of rod

$V=\dfrac{1}{4}\pi d^2h\\\Rightarrow V=\dfrac{1}{4}\times \pi\times (2.95\times 10^{-2})^2\times 92.6\times 10^{-2}$

Mass is given by

$m=\rho V\\\Rightarrow m=7800\times \dfrac{1}{4}\times \pi\times (2.95\times 10^{-2})^2\times 92.6\times 10^{-2}\\\Rightarrow m=4.93673144695\ kg$

Weight is given by

$W=mg\\\Rightarrow W=4.93673144695\times 9.81\\\Rightarrow W=48.4293354946\ N$

The weight of the rod is 48.4293354946 N

The mass of the rod is 4.93673144695 kg which is light. So, I will be able to carry the rod without a cart.

7 0

3 years ago

A car changes speed from 25 m/s to 10 m/s in 240 seconds. Describe its acceleration.

Dmitry_Shevchenko [17]

Explanation:

Acceleration is change in velocity over change in time:

a = Δv / Δt

a = (10 m/s - 25 m/s) / (240 s - 0 s)

a = -0.0625 m/s²

So the car decelerates at 0.0625 m/s².

7 0

4 years ago