Question

34)You find it takes 200 N of horizontal force tomove an unloaded pickup truck along a level road at a speed of2.4 m/s. You then load up the pickup and pump up itstires so that its total weight increases by 42% whilethe coefficient of rolling friction decreases by19%.
a) Now what horizontal force will you need to move the pickupalong the same road at the same speed? The speed is low enough thatyou can ignore air resistance.

Answer 1

Answer:

$F_H_n=230.04 N$

The Required  horizontal force is 230.04N

Explanation:

Since the velocity is constant so acceleration is zero; a=0

Now the horizontal force required to move the pickup is equal to the frictional force.

$F_H_n=F_f\\F_h=mg*u$

where:

F_{Hn} is the required Force

u is the friction coefficient

m is the mass

g is gravitational acceleration=9.8m/s^2

$200=mg*u$                         Eq (1)

Now, weight increases by 42% and friction coefficient decreases by 19%

New weight=(1.42*m*g) and new friction coefficient=0.81u

$F_H=(1.42m*g*.81u)$          Eq (2)

Divide Eq(2) and Eq (1)

$\frac{F_H_n}{200}=\frac{1.42m*g*0.81u}{m*g*u}\\F_H_n=1.42*0.81*200\\F_H_n=230.04 N$

The Required  horizontal force is 230.04N