If position vector r = bt^2i + ct^3j, where b and c are positive constants, when does the velocity vector make an angle of 450 with the x-and y-axes?

The velocity at time is

Take two vectors that point in the positive and positive directions, such as and . The dot products of the velocity vector with and are

and

We want the angles between these vectors to be 45º, for which we have . So

When , the velocity vector is equal to the zero vector, which technically has no direction/doesn't make an angle with any other vector. So the only time this happens is for

answer

c, on a nylon carpet in a dry area. give me brainliest

explanation:

its c its is a mixture of gases