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2) the driver of a 600kg sports car, heading directly for a railroad crossing 250m away, applies the brakes i a panic stop. the car is moving at 40m/s, and the brakes can supply a friction force of 1200N. a) how fast is the car moving when it reaches the crossing?
- i tried finding the change in time for this, thinking i could then find displacement from that, but it ended up as 2.5hours!
i then used f=ma and then average acceleration, got acceleration = 8... or neg 8... but then when i worked it out for change in velocity i got that the velocity was increasing, which can't be right seeing as the car is slowing down!?
any help appreciated!
3) a metre-stick is found to balance at the 29.7cm mark when placed on a fulcrum, when a 50g mass is attached at the 10cm mark the fulcrum must be moved to the 39.2 cm mark for balance. what is the mass of the meter stick?
- just plain stuck on this, tried about 3 different ways of attempting the question, but couldn't find one that suited! again, any help appreciated!
:)
- i tried finding the change in time for this, thinking i could then find displacement from that, but it ended up as 2.5hours!
i then used f=ma and then average acceleration, got acceleration = 8... or neg 8... but then when i worked it out for change in velocity i got that the velocity was increasing, which can't be right seeing as the car is slowing down!?
any help appreciated!
3) a metre-stick is found to balance at the 29.7cm mark when placed on a fulcrum, when a 50g mass is attached at the 10cm mark the fulcrum must be moved to the 39.2 cm mark for balance. what is the mass of the meter stick?
- just plain stuck on this, tried about 3 different ways of attempting the question, but couldn't find one that suited! again, any help appreciated!
:)