PHYSICS HELP - acceleration, static friction, etc.?

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PLEASE LABEL ANSWERS AND EXPLAIN BRIEFLY!


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A) Cathy takes the bus home from work. In her hand she holds a 2.0 kg cake box, tied together with a string. As she ascends the steps into the bus, the box accelerates upward with a rate of 2.5 metres/seconds^2. What is the force exerted on the string?





B) Cathy sets the box on the seat beside her. The bus accelerates from the rest to 60.0 km/hour in 4.0 seconds, and the box begins to slide. What is the coefficient of static friction between the box and the seat of the bus?





C) A taxi suddenly cuts in front of the bus, causing the bus driver to slam on the brakes. The bus driver reduces speed from 60.0 km/h to 20.0 km/h in 1.5 seconds. Does Cathy’s cake slide forward?

PHYSICS HELP - acceleration, static friction, etc.?
f) force of gravity 980cm/sec2 check its been a few years.





force on string is gravity +2.5/m/s^2





9.8+2.5= 11.3 m/sec^2





B) 0 to 60 km/hr in 4 seconds 6.66 m/s^2


cake held by gravity 980 cm/s^2





6.66/980= .006944 coefficient of static friction.





check the definition and math








c) yes conservation of momentum the bus brakes but the cake does not.

wisteria