#4
when an object is pushed by applied force it accelerated by
a = 5.9 m/s^2
now here we will have
m = 4.5 kg
now we can say that net force on the object is applied force and friction force
this net force is given by Newton's II law as
so friction force will be 11.45 N
#5
when an object is pushed by applied force it accelerated by
a = 6.5 m/s^2
now here we will have
m = 1.9 kg
now we can say that net force on the object is applied force and friction force
this net force is given by Newton's II law as
so applied force will be 17.95 N
#6
Given that
mass of hockey Puck = 0.8 kg
applied force on the puck = 570 N
acceleration of the puck = 682.5 m/s^2
now we can say that net force on the object is applied force and drag force of the air
this net force is given by Newton's II law as
so drag force due to air on the puck will be 24 N
#7)
Static friction is always stronger than sliding friction because in static situation of the object the bonding of the molecules of two surfaces will be very strong and hence it requires more force to start the motion, once the motion has been started the bonding of two surfaces becomes weak and then object can continue its motion with less friction.
#8
Given that
mass of box = 3.8 kg
applied force on the box = 27 N
acceleration of the box = 4.8 m/s^2
now we can say that net force on the object is applied force and friction force of the ground
this net force is given by Newton's II law as
so friction force due to ground on the box will be 8.76 N