What is the direction of the frictional force exerted on a coffee cup sitting on a stationary table?

A straight wire is positioned in a uniform magnetic field so that the maximum force on it is 4.0 N. If the wire is 80 cm long an

dusya [7]

Answer:

B = 2.5 T

Explanation:

F = 4 N

l = 80cm = 0.8 m

I = 2 A

B = ?

at maximum titha = 90degree

F = BILsin(thita)

sin90 = 1

F = BIL

==> B = F/IL

B= 4 ÷ (2×0.8)

B= 4 ÷ 1.6

B= 2.5 T

8 0

4 years ago

A 37 N block rests on a horizontal surface. The coefficients of static and kinetic friction between the surface and the block ar

Ne4ueva [31]

Answer:

The frictional force acting on the block is 14.8 N.

Explanation:

Given that,

Weight of block = 37 N

Coefficients of static = 0.8

Kinetic friction = 0.4

Tension = 24 N

We need to calculate the maximum friction force

Using formula of friction force

$f=\mu mg$

Put the value into the formula

$f=0.8\times37$

$f=29.6\ N$

So, the tension must exceeds 29.6 N for the block to move

We need to calculate the frictional force acting on the block

Using formula of frictional force

$f = \mu N$

Put the value in to the formula

$f=0.4\times37$

$f=14.8\ N$

Hence, The frictional force acting on the block is 14.8 N.

6 0

3 years ago

If the mass of the body is doubled what should be its speed so as to maintain the same kinetic energy ?

soldier1979 [14.2K]

Answer:

The speed should be reduced by 1/√2 or 0.707 times

Explanation:

The relationship between the kinetic energy, mass and velocity can be represented by the following equation:

K.E = ½m.v²

In this equation, the mass is inversely proportional to the square of the velocity or speed. This means that as the mass increases, the speed reduces by × 2.

Let; initial mass = m1

Final mass = m2

Initial velocity = v1

Final velocity = v2

According to the question, if the mass of the body is doubled i.e. m2 = 2m

½m1v1² = ½m2v2²

½ × m × v1² = ½ × 2m × v2²

Multiply both sides by 2

(½ × m × v1²)2 = (½ × 2m × v2²)2

m × v1² = 2m × v2²

Divide both sides by m

v1² = 2v2²

Divide both sides by 2

v1²/2= v2²

Square root both sides

√v1²/2= √v2²

v1/√2 = v2

v2 = 1/√2 v1

This shows that to maintain the same kinetic energy if the mass is doubled, the speed should be reduced by 1/√2 or 0.707 times.

8 0

3 years ago

A bicycle travels 6.10 km due east in 0.210 h, then 11.30 km at 15.0° east of north in 0.560 h, and finally another 6.10 km due

Virty [35]

Answer:

Explanation:

Given

First bicycle travels 6.10 km due to east in 0.21 h

Suppose its position vector is $r_1$

$r_1=6.10\hat{i}$

After that it travels 11.30 km at $15^{\circ}$ east of north in 0.560 h

suppose its position vector is $r_2$

$r_{2}=11.30\left ( cos15\hat{j}+sin15\hat{i}\right )$

after that he finally travel 6.10 km due to east in 0.21 h

suppose its position vector is $r_3$

$r_{3}=6.10\hat{i}$

so position of final position is given by

$r=r_1+r_{2}+r_{3}$

$\vec{r}=15.12\hat{i}+10.91\hat{j}$

$\vec{v_{avg}}=\frac{\vec{r}}{t}$

t=0.21+0.56+0.21=0.98 h

$\vec{v_{avg}}=15.42\hat{i}+11.13\hat{j}$

$|v_{avg}|=\sqrt{361.71}=19.01 km/hr$

For direction

$tan\theta =\frac{11.13}{15.42}=0.721$

$\theta =35.791^{\circ}$ w.r.t to x axis

5 0

4 years ago

A motorcycle of 170 kg is moving with a velocity 25m/ . Calculate the kinetic energy

topjm [15]

Answer: 53125joules

Explanation: The formula for kinetic energy is 1/2mv^2.

So we would have

1/2[(170)(25x25)]=53125

3 0

3 years ago