Do you calculate gravity when you calculate friction

1. As long as the pressure branch generated by gravity is not zero and the contact surface is not deformed by pressure, the relationship between gravity and friction is proportional.

2. No friction coefficient
you don't know whether you can push or not
F = UMG (friction coefficient when u)
but if you can't push, friction is equal to thrust
pushing friction is equal to UMG
friction is divided into dynamic friction and static friction
if the object doesn't move relative to each other, there is no dynamic friction
dynamic friction f = UMG (U is dynamic friction coefficient 0 < U < 1), which is also the maximum static friction Force
if there is no dynamic friction coefficient, the maximum static friction can not be determined
for your problem,
if the object has relative motion, then the dynamic friction = UMG (regardless of the uniform speed, If there is no relative motion,
then the static friction is always equal to the thrust so that the two forces can be balanced
the above is the theory
let's analyze your problem
the first g = 10
F = 3
because 0 < U < 1
then the maximum static friction in the range of 0 < f < 10N
may be less than f or greater than f
so it is not necessary It can judge whether the object is moving or not
but as you said that even the motion is a straight line with uniform speed
the size of F can definitely be 3N
(force balance)
similar to question 2
3
the maximum static friction must be less than the thrust f
so the object must move
but it cannot be uniform
because the thrust is greater than the friction
so these two questions can judge whether the object can move, But we can't determine the amount of friction

3. Starting point: West Campus of Jinan University
start from West Campus of Jinan University, walk to Jinan University, take Ji Chang bus No.1, get off at jingwuwei 12, walk to jingsiwei 10, transfer to No.101, get off at Central Hospital, and walk to Jinan central hospital
Terminal: Jinan central hospital

4.

The railway hospital is at the intersection of Jingba road and Qingnian West Road

Jinan University is divided into Shungeng Road Campus and Jiwei road Second Ring South Road intersection campus. I don't know who you are. But it's usually the one at the intersection of Jiwei road and 2nd Ring South Road. So, choose there as the starting point. Please refer to the bus route

bus line: no.k301, the whole journey is about 8.7km

1. Take no.k301 from Jinan University, pass 3 stops, and reach the Provincial Sports Center Station

2. Walk about 830m to Jinan Railway Central Hospital

5. If you are in the West Campus of Jinan University, you can take bus No.102 and get off at the west entrance of Jingqi Road, then walk to Jingshi Road and take bus No.117 and get off at Shanshi East Road

if you are in Quancheng College of Jinan University, you can take bus NO.48 to Qianfo Mountain and transfer to bus No.117

6.

As of July 2016, the bus stop of brt6 in Jinan City, which is closer to Jinan University, is the bus stop of Dongyuan District of provincial hospital. Passengers can take a bus from Jinan University to the East Hospital bus station of the provincial hospital, and then get off and transfer to brt6 bus

bus line: K301, the whole journey is about 18.4km

1. Walk about 70m from Jinan University to Jinan University Station

2. Take K301, after 6 stops, to the Eastern Hospital Station of provincial hospital

7.

bus route: No.2 Jichang bus, the whole journey is about 9.8 km

1. Walk about 10 meters from Jinan University to Jinan University Station

2. Take No.2 Jichang bus, pass 7 stops, and reach the long-distance bus terminal

3. Walk about 50 meters to Jinan long-distance bus terminal

8.

Take bus k155 from the West Campus of Jinan University to the west gate, get off at Xiba bus station, and then transfer to bus K137 to tourist road