A car that weighs 12000.0 N is initially moving at a speed of 30.0 km/hr when the brakes are applied and the car is brought to a stop in 4.1 s. Find the magnitude of the force that stops the car, assuming it is constant. This is the wrong problem ^^^ A 6.70 kg penguin runs onto a huge horizontal sheet of frictionless ice. The sheet lies on the xy-plane. At t = 0 s it is at x = 0 m and y = 0 m with an initial speed of 0.75 m/s along the positive x-axis. It slides while being pushed by the wind with a force of 0.37 N directed along the positive y-axis. Calculate the penguin's speed at t = 8.75 s. F=ma => 0.37=6.7a => a=0.6 m/s^2 vy(t )= vy0 + at = 0 + .06(8.75) = 0.483 m/s v(t)^2 = vx(t)^2 + vy(t)^2 = 0.75^2 + 0.483^2 = 0.796 v(t) = 0.892 m/s This part is CORRECT. Calculate the direction of his velocity at that time. Give the angle with respect to the x-axis. Set the vectors up as a right triangle, find the angle between the resultant vector and the x-vector. x-vector: 0.75 m/s y-vector: 0.483 m/s angle should be: sin^-1(y/x) = sin^-1(.483/.75) = 40.1 deg This part is INCORRECT. What did I do wrong?