Question

A rock is dropped from the top of a tall building. The rock's displacement in the last second before it hits the ground is 40 %% of the entire distance it falls. How tall is the building?

Answer #1

Let, Height of building = H

Let, Time taken by rock to reach the ground = T

Given, initial velocity of rock=0

Dispalcement of rock in last second =

We know that displacement covered in last second is given by

also , ----------------1)

So, -------------2)

Dividing 1) and 2)

so, T=4.40s

Putting this value of T in equation 1),we get hieght of building as

A rock is launched from the top of a building 50 m high at an
angle of 30o with a speed of 20 m/s. (a) How far from
the building does the rock land? (b) What is the rock's maximum
altitude as measured from the ground? (c) What is the velocity of
the rock just before landing?

A steel ball (78 kg) is dropped from the top of a 370m tall
building. It lands in a
snowbank, creating a crater 1.1m deep. The speed of the ball is
35m/s just before
it hits the snowbank.
(a) Calculate the work done by the snow in bringing the ball to
rest.
(b) Calculate the magnitude of the force exerted on the ball by the
snow (assuming
the force is constant).
(c) Calculate the work done by air drag before...

1. Two identical eggs were thrown at the same time from the top
of a building of height 100 m at a speed 20. One egg was thrown at
an angle 40° above the horizontal while another was thrown at the
same angle but below the horizontal. How long does it take for the
other egg to hit the ground after the one of the eggs hits the
ground?
Does the time difference between the eggs hitting the ground
depend...

A man stands on the roof of a 19.0 mm -tall building and throws
a rock with a velocity of magnitude 30.0 m/sm/s at an angle of 42.0
∘∘ above the horizontal. You can ignore air resistance.
Calculate the maximum height above the roof reached by the
rock.
Calculate the magnitude of the velocity of the rock just before
it strikes the ground.
Calculate the horizontal distance from the base of the building
to the point where the rock strikes...

If there is no air resistance, a quarter dropped from the top of
New York’s Empire State Building would reach the ground 9.6 s
later. (a) What would its speed be just before it hits the ground?
(b) How high is the building?

A rock is tossed straight up from ground level with a speed of
25 m/s. When it returns, it falls into a hole 25 m deep. (a) What
is the rock's velocity just before it hits the bottom of the hole?
(b) How long is the rock in the air, from the instant it is
released until it hits the bottom of the hole? (c) What is the
total distance travelled by the rock from the point of throw to...

A rock is thrown from the top of a building 80 m high, with a
speed of 14 m/s at an angle 25 degrees above the horizontal. When
it hits the ground, what is the magnitude of its velocity (i.e. its
speed).

A
ball is dropped from rest from the top of a 6.10 m-y’all building,
falls straight downward, collides inelasrically with the ground,
and bounces back. The call loses 10.0% of its kinetic energy every
time it collides with the ground. How many bounces can the ball
make and still reach a windowsill that is 2.44 m above the
ground?

A brick is dropped from the roof of a tall building. After it
has been falling for a few seconds, it falls 35.0 m in a 1.00-s
time interval.
What distance will it fall during the next 1.00 s? Ignore air
resistance.
Express your answer with the appropriate units.

A 4.1-kg ball is thrown from the top of a 4-m tall building
(point A) with a speed of 1 m/s at an angle 2 degrees above the
horizontal. If air resistance is negligible, what is the value of
the kinetic energy of the ball as it hits the ground?

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 5 minutes ago

asked 5 minutes ago

asked 6 minutes ago

asked 7 minutes ago

asked 7 minutes ago

asked 15 minutes ago

asked 15 minutes ago

asked 18 minutes ago

asked 18 minutes ago

asked 23 minutes ago

asked 23 minutes ago

asked 26 minutes ago