Într-un calorimetru se pune o masă de 200 g alcool cu temperatura de 30 °C și apoi se adaugă o bilă de plumb cu temperatura de 80 °C. Știind temperatura lor de echilibru de 50 °C, determină cât cântărește bila de plumb. Se dă: căldura specifică a alcoolului 2430 J/kg∙K și cea a plumbului de 130 J/kg∙K.

A3.9 g aluminum foil ball with a charge of +4.1×10−9 c is suspended on a string in a uniform horizontal e⃗ field. the string deviates to the right and makes an angle of 30∘ with the vertical. part a part complete what information about the e⃗ field can you determine for this situation? what information about the field can you determine for this situation? only the magnitude of e⃗ only the direction of e⃗ both the magnitude and the direction of e⃗ none of the above previous answers correct part b determine the magnitude of the electric field. express your answer with the appropriate units. e e = nothing nothing request answer part c determine the direction of the electric field. determine the direction of the electric field. to the right to the left away from you toward you

Ablock having mass m slides down an inclined plane. the force of friction between the block and the inclined plane is f, the block's weight is m g, and the normal force is n. (a) draw a free – body force diagram showing the forces acting on the block. (b) write down all relevant newton’s equations for a given situation.

The record distance in the sport of throwing cowpats is 81.1 m. this record toss was set by steve urner of the united states in 1981. assuming the initial launch angle was 45° and neglecting air resistance, answer the following. (a) determine the initial speed of the projectile. m/s