The cart impacts the safety barrier with speed v0 = 3.25 m /s and is brought to a stop by the nest of nonlinear springs which provide a deceleration a = −k1x − k2x3 , where x is the amount of spring defl ec- tion from the undeformed position and k1 and k2 are positive constants. if the maximum spring defl ec- tion is 475 mm and the velocity at half-maximum defl ection is 2.85 m /s, determine the values and cor- responding units for the constants k1 and k2.

If a refrigerator is a heat pump that follows the first law of thermodynamics, how much heat was removed from food inside of the refrigerator if it released 380j of energy to the room?

Boxing gloves are padded to lessen the force of a blow. (a) calculate the force exerted by a boxing glove on an opponent’s face, if the glove and face compress 7.50 cm during a blow in which the 7.00-kg arm and glove are brought to rest from an initial speed of 10.0 m/s. (b) calculate the force exerted by an identical blow in the gory old days when no gloves were used and the knuckles and face would compress only 2.00 cm. (c) discuss the magnitude of the force with glove on. does it seem high enough to cause damage even though it is lower than the force with no glove?

5g of ammonium nitrate was dissolved in 60g of water in an insulated container. the temperature at the start of the reaction was 23.0°c and at the end it was 19.0°c. calculate the energy absorbed by the reaction.