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# is mise lisa

Questions7
• ### Should i choose chemistry or biology for my undergraduate degree?

I'm going into second year science in Ireland and cannot decide whether to study subjects like microbiology and biochemistry or should I go down the straight chemistry route or pharmaceuticals? Any help and advice would be greatly appreciated!! Thanks

• ### chemistry problem...10 points for first correct answer?

What mass of KCl is needed to precipitate the silver ions from 18.0mL of 0.110M AgNO3 solution?

A certain volume of a 0.80M solution contains 4.6g of a salt. What mass of the salt is present in the same volume of a 2.9M solution?

An object of mass 5.0 kg is pulled along a smooth horizontal table by means of two forces, one of 40 N along the x-axis (horizontal) and one of 30 N along the y-axis (vertical).

(a)What is the acceleration of the object?

(b) What is the normal (reaction) force acting on the object on the table?

(c) What would the acceleration be, if the two forces, instead of being horizontal, had been directed upwards at 15 to the horizontal? What would the normal (reaction) force be in this case?

The acceleration due to gravity (g) is 9.8 m s-2.

• ### Force question...first correct answer gets 10 points?

A 20 kg package is being dragged across the surface of a smooth horizontal surface by means of two horizontal ropes. One rope exerts a force of 100 N south-east while the other exerts a force of 200 N south-west. Determine the acceleration (magnitude and direction) of the package.

A bullet of mass 15g travelling with a velocity of 150m/s strikes a tree and penetrates a distance of 250mm into the timber before coming to rest. What was the average acceleration of the bullet and what was the average force causing the acceleration?

What velocity would the bullet need to penetrate to a depth of 300mm?

All help greatly appreciated. Thanks

• ### friction question...need help!!!!?

A child pulls a hollow empty box of mass 1.0kg along a smooth (frictionless) floor by means of a string attached to the box so that the string is horizontal. Calculate the tension in the string when the box is accelerating at 1.5ms^-2?

A toy is placed in the box and the acceleration is reduced to 0.5ms^-2 with the same force. What is the mass of the toy?

I 've done the question but not sure if i have the correct answer. Any help greatly appreciated. Thanks