Can someone me with these physics problems? i just don’t even know where to start.

#1

for the block of mass 5 kg normal force is given as

friction force is given as

Net force is given as

now we know that

#2

Normal force is given as

now we know that

as object moves with constant velocity

now for coefficient of friction we can use

#3

net force upwards is given as

mass is given as

now as per newton's law we can say

#4

As we know that when block is sliding on rough surface

part a)

net force = applied force - frictional force

part b)

for coefficient of friction we can use

here normal force is given as

now we have

#5

if an object is initially at rest and moves 20 m in 5 s

so we can use kinematics to find out the acceleration

now net force is given as

#6

an object travelling with speed 25 m/s comes to stop in 1.5 s

so here acceleration of object is given as

now the force is gievn as

the answer is 12 as i may remember

: )

snell's law

refractve index = sin incidence / sin refraction