A track athlete throws a 2kg discus into a field with a velocity of 21m/s. What is the momentum of the discus?

Given :

Momentum of disc = 42 kg m/s

Velocity of disc = 21 m/s

To Find :

Mass of the disc.

Solution :

❖ Momentum is defined as the product of mass and it's velocity..

Mathematically, p = m × v

p denotes momentum

m denotes mass

v denoted velocity

➛ It is a vector quantity having both magnitude as well as direction.

➛ It can be positive, negative or zero.

➛ SI unit : kg m/s or N s

By substituting the given values;

➙ p = m × v

➙ 42 = m × 21

➙ m = 42/21

➙ m = 2 kg

∴ Mass of the object is 2 kg.

Knowledge BoosteR :

As per newton's second law of motion, force is measured as the rate of change of linear momentum.

Formula : F = dp / dt

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.