Consider a cart being pulled by a horse with constant velocity. The horse exerts force `vecF_((C )/(h))` on the cart. (The subscript indicate the force on the cart due to horse.). The first subscript denotes the body on which force acts and second due to which it acts.
Choose the statements(s):

Options

A. `vecf_(C//g), vecN_(C//g), vecN_(h//g)` are external force on a system consisting of a horse and a cart.
B. `vecf_(C//g)vecN_(C//g)vecN_(h//g)`
C. `vecN_(C//g)` and `vecF_(C//E)` are action reaction pairs.
D. `vecF_(C//h)vecF_(h//C)` are action reaction pairs

Answer

A, B, C

Explanation

a. For the system of `(horse+cart), only vecF_(c//h)` and `vecF_(h//c)` will be internal forces. All other forces will be external.
b. As (horse`+`cart) system is moving with constant velocity, so net horizontal force on it should be zero.
For this `vecF_(h//s)+vecf_(c//s)=0`
`vecN_(C//g) and vecF_(C//E)` cannot be action - reaction pairs, as they act on the same body.
d. `vecF_(C//M) and vecf_(h//C)` are action reaction pairs.