Which is greater `mu_s` or `mu_k`?

Which sample contains greater number of nuclei ? a 5.00 -mu Ci sample of .^240 Pu (half-life 6560 y ) or a 4.45-mu Ci sample of .^243 Am (half-life 7370 y ).

Assetion: Carbon dioxide has greater value of root mean square velocity mu_(rms) than carbon monoxide. Reason: mu_(rms) is inversely proportional to molar mass.

A sufficiently long plane of mass 4kg is placed on a smooth horizontal surfaces A small block of mass 2kg is placed over the plank and is beging acted upon by a time verying horizontal force F = (0.5t) where F is in newton and t is in second as shown in figure. The coefficient of friction slipping the plank and the block is given is mu_(s) = mu_(k) = mu time t = 12s the relative slipping between the plank and the block is just likely to accor The coefficient of friction mu is equal to

A particle is at rest on a rough horizontal plane . The plane is slowly titled until the particle starts to move and is then kept fixed . If the static and kinetic coefficients of friction are mu_(s) and mu_(k) ( lt mu_(s)) respectively , show that the velocity of the particle after it has travelled distance d is given by : v = sqrt((2(mu_(s) - mu_(k))"gd")/((1 + mu_(s)^(2))^(1//2)))

A block of mass m rests on a rough horizontal plane having coefficient of kinetic friction mu_(k) and coefficient of static friction mu_(s) . The spring is in its natural, when a constant force of magnitude P=(5mu_(k)mg)/(4) starts acting on the block. The spring force F is a function of extension x as F=kx^(2).( Where k is spring constant ) (a) Comment on the relation between mu_(s) and mu_(k) for the motion to start. (b) Find the maximum extension in the spring ( Assume the force P is sufficient make the block move ) .

Repeat the above problem, if instead of mu , we are given mu_(s) and mu_(k) ,where mu_(s) =0.6 and mu_(k) =0.4 .

Which is true for rolling friction ( mu _(r ) ) , static friction ( mu_(s)) and kinetic friction ( mu_(k)) ?

The sum of the distinct real values of mu for which the vectors mu i+j+k , i+mu j+k , i+j+mu k are coplanar is