You're driving at speed v_0 when you spot a stationary moose on the road, a distance d ahead. find an expression for the magnitude of the acceleration you need if you're to stop before hitting the moose. explain .

The formula that is applicable in this problem is the formula in kinematics vf^2 = vi^2 + 2ad 
Initial velocity = Vi Final velocity = 0 (as the car stops) Distance travelled = d 
vf^2 = vi^2 + 2ad  (0)^2 = (Vi)^2 + 2ad  0 = (Vi)^2 + 2ad  2ad = -(Vi)^2 a = - (Vi)^2 / (2d)

We can’t really help considering you didn’t finish what you were saying.