0:00:00.000,0:00:03.000 If you happen to drive a car with a manual transmission 0:00:03.000,0:00:07.000 and you've ever let the battery die, well, there's a good chance you've had to push your car. 0:00:07.000,0:00:10.000 Let's talk about the forces involve in pushing a car. 0:00:10.000,0:00:12.000 Let's say we're lucky enough to have 3 people pushing this car. 0:00:12.000,0:00:17.000 Our green- and purple-haired doctors and, oh I don't know, Albert Einstein. 0:00:17.000,0:00:19.000 Let's say we're looking at this car from above. 0:00:19.000,0:00:23.000 Here's our bird's-eye view of the car--from above--and the mass of this car is 1000 kg. 0:00:23.000,0:00:28.000 Let's say Einstein is pushing from directly behind--here's the top of Einstein's head, 0:00:28.000,0:00:30.000 and there are his arms. 0:00:30.000,0:00:33.000 The green-haired doctor is pushing from the side at a small angle, you'll notice. 0:00:33.000,0:00:37.000 The purple-haired doctor is pushing from the other side, also at a small angle. 0:00:37.000,0:00:40.000 Let's say an interesting fact about this group of friends 0:00:40.000,0:00:43.000 is that they can all push with exactly the same force. 0:00:43.000,0:00:47.000 When they all push on this car at that same time with this exact same force, 0:00:47.000,0:00:51.000 the acceleration of the car is 0.5 m/s². 0:00:51.000,0:00:56.000 The angle that the green- and purple-haired doctors are pushing at we'll call α. 0:00:56.000,0:01:00.000 For this problem α is 30 degrees, so they're pushing at a 30-degree angle. 0:01:00.000,0:01:04.000 Einstein here is pushing directly up on the back of the car, 0:01:04.000,0:01:06.000 but these guys are doing it at a 30-degree angle. 0:01:06.000,0:01:10.000 I want you to tell me with what force is each person pushing. 0:01:10.000,9:59:59.000 Enter your answer here in Newtons.