Please can someone verify if these statements are TRUE or FALSE. I have placed some of the answers but do not know if they are okay.

(F ) 1. The value of the universal gravitation constant is equal to 6.67x10-11 N.m2/kg2.

( F ) 2. The acceleration due to gravity at the surface of the Earth is directly proportional to the mass of the Earth and inversely proportional to the square of its radius.

( F) 3. The unit in the International System of gravitational potential energy is the newton.

( T ) 4. The friction force is a force that opposes the relative movement between two bodies in contact.

( F) 5. The resultant force on a body is 200N, the mass of the body is 40 kg, so its acceleration is 9.8 m/s2.

( ) 6. When a body moves on a wooden surface, its friction force is 28 N, so the normal force exerted by the wood on the body is 56N. k =0.5 and s=0.7

(F ) 7. A force is conservative if the work it does around any closed path is nonzero.

(T ) 8. The average speed of an air molecule at room temperature is approximately 500 m/s, with an average molecular mass of 6x10-25 kg; therefore, its momentum is 3x10-22 kg.m/s.

(T ) 9. When a force is applied to an object for a certain time, the object experiences an impulse or momentum.

( ) 10. The weight of an object is the gravitational attraction between the Earth and the object.

( ) 11. The value of g at 400 km above the surface of the Earth, where the International Space Station is in orbit, is equal to 8.67m/s2?

( F) 12. The unit in the International System of pressure is joule.