Question 1
- When the local time is 2.00pm at longitude 450, what is the longitude of a place whose local time is 8.00pm?
- Name three forces responsible for the spheroid shape of the earth.
Answer
- 450E X
2pm 8pm 6 hrs
15 = 1h
= 6h - 900
90 + 45 = 1350 - - Gravitational force
- Centipetal force
- Centrifugal force
Question 2
- Name the two scales used to measures the intensity of an earthquake.
- State any two human causes of earthquake.
Answer
- - Ritcher scale
- Mercalli scale
- Rossi scale - (i) Passage of large trucks and trains over areas with weak rocks.
(ii) Using explosives during mining.
(iii) Establishment of large reservoirs cause slips on weak rocks.
(iv) Use of nuclear bomb
Question 3
- A part from the core name two other layers that make up the internal structure of the earth.
- Give three characteristics of the core.
Answer
- - Mantle
- Crust - - Has radius of about 3500 km.
- Made up of two layers – outer and inner.
- Outer core is about 2300 km thick
- Temp. is aprox. 37000
- Main minerals are iron and nickel.
- Average density is about 17.5g/cc
Question 4
- Name two features formed due to faulting.
- State two effects of faulting on drainage.
Answer
- - Rift valley
- Block mountain/horst block
- Tilt block
- Fault step
- Escarpment/fault scarp
- Formation of waterfa - - It may change the direction of flow.
- Disappearance of a River.
- May cause a Reverse drainage
- Formation of depressions which may form lakes.
Question 5
- Differentiate between weathering and mass wasting.
- State two negative effects of mass wasting.
Answer
- Weathering is the process of rock disintegration forming soil without movement (insite) while mass wasting is the downward movement of weathered materials by gravity.
- - Formation of scars on the land.
- Triggers off soil erosion.
- A landslide can block a river causing it to change direction of flow.
- Mass of materials from landslides can block a river and form a lake on the up stream.
- Forms new landforms at the base of a landslide