Question

premouS11 Problem 7.41 Part A The 1.5 kg physics book in figure is connected by a string to a 450 gcoffee cup. The book is given push up the slope and released with a speed of 3.3 m/s. The coefficients of friction are A How far does the book slide? a Express your answer with the appropriate units 0.50 and A-0.20 (Figure!) 丨 0.59m Figure 1 of Submit Manswers Give Up Incorrect; Try Again Part B At the highest point, does the book stick to the slope, or does it slide back down? 20° O O stick to the slope slide back downhill Submit My Answers Give Up Provide

Answer 1

here,

mass of book ,m1 = 1.5 kg

mass of cup , m2 = 0.45 kg

uk = 0.2

the accelration , a = net force/effective mass

a = ( m1 * g * sin(theta) + m2 * g + uk * m1 * g * cos(theta))/( m1 + m2)  

a = ( 1.5 * 9.81 * sin(20) + 0.45 * 9.81 + 0.2 * 1.5 * 9.81 * cos(20))/( 1.5 + 0.45)

a = 6.26 m/s^2

let the distance travelled before stopping be s

v^2 - u^2 = 2 * a * s

0 - 3.3^2 = - 2 * 6.26 * s

s = 0.87 m

b)

the downward force , Fd = m1 * g * sin(theta) + m2 * g

Fd = 1.5 * 9.81 * sin(20) + 0.45 * 9.81 N

Fd = 9.44 N

the static frictional force , ffs = us * m1 * g * cos(theta)

ffs = 1.5 * 0.5 * 9.81 * cos(20) = 6.91 N

as Fd > ffs

the block will slide downwards