A car with a mass of 900 kg rounds an unbanked curve in the road at a speed of 45.0 m/s. If the radius of the curve is 100 m, what is the average centripetal force exerted on the car?

Space-time metric ds2= -dt2+at2dx2+bt2dy2+ct2dz2 (a)how does the area of a rectangle with vertices at ( x=0, y=0, z=0 ), (1,0,0 ), ( 0,1,0 ) and (1,1,0 ) changes with time? (b) if a photon moving in the x direction starts from the origin at t=1, when does it reach x=l? (ds=0 for the trajectory of a photon.) (c) the proper time for a particle is defined by cd=ds. what is the proper time for a particle to move along the trajectory ( x(t)=t, y(t)=0, z(t)=0 ) from t=0 to 1 ? what is the condition on the parameter a so that the velocity of the particle never exceeds the speed of light ?

All the simple machines make work easier to do by changing the or of a force. a. size; type b. work; type c. size; direction d. type; direction

Acaterpillar tries to climb straight up a wall a meter high, but for every 2 cm up it climbs, it slides down 1 cm. eventually, it reaches the top. when it reaches the top, it does not pull itself over so it will slide down 1 cm. what is the total displacement traveled?