# A 55-kg box rests on a horizontal surface. The coefficient of static friction between the box and the surface is 0.30. A horizontal 140-n force is applied to the box. What is the friction force on the box?

The friction force on the box is 161.7 N

Explanation:

given information:

m = 55 kg

μs = 0.30

F = 140 N

To calculate the friction force, we use the following formula:

F(friction) = μs N,

N is normal force

N -  W = 0

N = W

= m g

Thus,

F(friction) = μs N

= μs  m g

= 0.3 x 55 x 9.8

= 161.7 N

## Related Questions

A ferris wheel is 35 meters in diameter and boarded from a platform that is 2 meters above the ground. The six o'clock position on the ferris wheel is level with the loading platform. The wheel completes 1 full revolution in 6 minutes. The function h = f(t) gives your height in meters above the ground t minutes after the wheel begins to turn. Write an equation for h = f(t).

Explanation:

Amplitude is 35/2=17.5

Midline= Distance from ground + Amplitude = 17.5+3= 20.5

Period is time taken to finish 6 minutes

2π/b=T

2π/b=6

b=π/3

Explanation:

As we know that time period of the ferris wheel is given as

so we have

now angular position at any time "t" is given as

so the height as a function of time is given as

A small object carrying a charge of -3.00 nc is acted upon by a downward force of 30.0 nn when placed at a certain point in an electric field.

The working equation for this one is:

E = F/Q, where E is the strength of the electric field, F is the electric force and Q is the charge. Substituting the corresponding values, the strength of the electric field is equal to

E = -30 nN/-3 nC
E = 10 nN/nC

X(t)= 0.0945t^4 - 0.171^3 + 0.751^2 +4.53t -6.07
find the acceleration if t= 2.77s

The acceleration at t = 2.77 s is 7.36 m/s².

Explanation:

As we know that acceleration is determined by the rate of change in velocity and velocity is determined as the rate of change in distance. So indirectly, acceleration can also be determined as the second order differentiation of distance.

Such as and

So,

As here the x is given as function of t as

So first to determine the velocity, we have to differentiate the above function with respect to t, and the answer is

Now, to find the acceleration, we have to again differentiate this with respect to t. So the final answer is

So as the time is given as t = 2.77 s, substitute this in above equation, to determine the acceleration at this time. So the answer will be

a=8.701-2.842+1.501=7.36 m/s².

Thus, the acceleration at t = 2.77 s is 7.36 m/s².

How many turns are in the secondary coil of a step up transformer that increases voltage from 30 V to 150 V and has seven turns in the primary coil?