A body weighing 5 kgf, placed on a surface of area 0.1 m², exerts a thrust on the surface equal to:

1. 50 kgf
2. 5 kgf
3. 50 kgf m^-2
4. 5 kgf m^-2

The unit of thrust is:

1. kgf
2. kg
3. g
4. m s^-1

The feet of lizards act like:

1. moving pads
2. drilling pads
3. suction pads
4. none of the above

The unit of pressure is:

1. N x m
2. kgf
3. N m^-2
4. kgf m²